


f^^mmmmmi 





<Ehemistry 
ITS Evolution 
AND Achievements 






f G WiECHMANN 



SCIENCE SKETCHES 



CHEMISTRY 

ITS 
EVOLUTION AND ACHIEVEMENTS 



BY 

Ferdinand G. Wiechmann, Ph.D. 




NEW YORK 

WILLIAM R. JENKINS 

851-853 Sixth Avenue 

1899 

M 



TWO COPIES RECEIVEID, 

Library of Congrd8% 
Office f tha 

MOV 1 6 I W 

. Reglstir of Copyright^ 



56212 



Copyright, i8gg, by F, G. Wiechmann 
[A// rights reserved^ 






PRESS OF 

WILLIAM R. JENKINS 

NEW YORK 






WITH LOVE 

TO 

MY WIFE 



PREFACE, 



It seems to the writer that space might 
be found on the bookshelves of lovers of 
knowledge for some modest volumes, 
which, without wish or pretence to dis- 
place any learned treatises on the topics 
they discuss, would offer to their readers 
a correct and concise synopsis of the 
subjects they consider. 

Works of this description, — Science 
Sketches would seem an appropriate 
designation for them, — should prove wel- 
come to all who take a general interest 
in science. They should be of value to 
students entering upon some special field 
of study, presenting them with a general 
survey of their chosen ground, and per- 
chance might be acceptable even to 
workers in various branches of science, 
affording them a ready acquaintance with 
the trend of thought in domains of learn- 
ing other than their own. 

Some knowledge of the various phases 
through which a science has passed is, 



moreover, of value in teaching one to 
place a more j ust — perhaps it were better 
to say, a more modest — estimate on the 
theories of the day. For, while it is 
indisputable that a truth once discovered 
is never lost, although the form in which 
it is embodied may be altered, yet it is 
also beyond question that doctrines and 
dicta pass away, even as the men who 
formulate and pronounce them. 

The aim to enlist the interest of non- 
professional readers in an exact science, 
is an undertaking not without its diflS- 
culties. On the one hand, care must be 
taken not to ground on the shoals of 
superficiality; on the other, heed must 
be had not to drift into currents which 
w^ould speedily carry beyond touch of all 
soundings. The selection of a course 
that shall pass clear of either danger 
certainly calls for the exercise of careful 
consideration. 

Preparation of this sketch, "Chem- 
istry: its Evolution and Achievements,'' 
has been attempted on the lines indi- 
cated. It is submitted to its readers in 
the hope that the grandeur and the 
charm of the science may prove discern- 
ible even through the veil of an inade- 
quate presentation. 



The writer's indebtedness to the au- 
thors he has consulted, is indicated by a 
list of their works which is appended ; 
acknowledgment is furthermore grate- 
fully made of his special obligations to 
the classic writings of Hermann Kopp, 
the great historian of chemistry. Many 
of the chronological data, appearing in 
the index of names, were secured from 
various journals, biographies, dictionaries 
and encyclopaedias. 

F. G. W- 

Manhattan, 



Vll 



CHEMISTRY: 

ITS 
EVOLUTION AND ACHIEVEMENTS. 



La pensee et la matiere — thought and 
matter, was the explanation of Rodin, 
the sculptor, when asked about the 
significance of one of his beautiful crea- 
tions, — a woman's head, broad of brow 
and of thoughtful mien, emerging from, 
3^et fettered by, the rock w^hich gave it 
life. 

Xo representation more fitting than 
this could be selected should one seek to 
symbolize the Birth of Chemistry, 

Chemistry, the science of matter, has 
taken origin in, and rests upon, a basis 
of fact broad, massive, secure. 

Even as aeons have measured the slow 
accretion of the rock w^hich has so admi- 
rably served the sculptor's purpose, thus 
passing ages have witnessed the gradual 
accumulation and slow growth of the ma- 
terial from which there has been wrought 
the science of chemistry we know to-da3\ 



Origin Its beginnings are lost in the haze of 
istry ^^^ remote past and undoubtedly date 
back thousands of years to the time when 
the pressing needs of man taught him to 
adapt to his own ends the means and the 
materials which Nature placed at his 
disposal. 

Passing beyond the domain of history 
and entering the realm of legend and 
tradition, we learn that the first to re- 
ceive instruction in chemical lore was — 
woman. 

Thus, in the book Henoch^ originally 
written about 115-110 B.C., account is 
given of intimate relations existing be- 
tween certain angels and some denizens 
of this world. 

One of these angels, Azazel, is said to 
have taught women some of his arts, the 
making *'of jewelry and the use of rouge, 
and the beautifying of the eyebrows, and 
the most valuable and choice stones, and 
all coloring-matters, and the metals of 
the earth.'' 

This legend is also met with in the 
Homilies^ formerly ascribed to Clemens 
Romanus, and it recurs in the following, 
the third, century, in the writings of 
TertuUianus, De cultic feminarum, Zo- 
simos, who probably lived in the fourth 
2 



century, likewise quotes this story. It 
would thus appear that even in those 
days chemistry was held to have been 
imparted to mankind in a distant past. 

In some of the earlier writings of the 
alchemists these legends re-echo, for 
they also express the belief that chem- 
istry, in the sense then attached to the 
w^ord, had first been confided to woman 
by superior beings. In a script claimed 
to have been addressed by Isis to her son. 
Horos, Isis relates that she had imposed, 
on the angel Amnael, as the price of her 
favor, the condition that he teach her the 
secret of making gold and silver; she 
furthermore states that she had succeeded 
in obtaining the fulfillment of her desire. 

But recently news has come from the 
far East that Monsieur E. x\melineau lias 
discovered, at Abydos, in Eg3'pt, the 
tombs of the god-kings Osiris, Seth and 
Horos. This discovery would seem to 
remove from the realm of myth-land,, 
Osiris, Isis (his sister-wife, for her name 
is mentioned on the tomb), and Horos, 
their son; it seems to place before us tan- 
gible evidence of the existence of mortals, 
who lived ten thousand years ago. 

May we hope that this tomb, whose 
silence of ages has at last been broken, 

3 



will yield some clue to the fabled, price-' 
less secret of Isis ? For, have we not the^ 
testimony of Zosimos to the effect that 
precepts for the making of gold were 
hewn in stone in the temple of the 
Egyptian god Pthah ? 

A legend to be found in the chronicles- 
of John of Antioch (about the seventh 
century) would interpret the story of the 
golden fleece as a record of the art of 
making gold by chemical means ; these 
directions were said to have been in- 
scribed upon the skin of an animal. 

There seems to be no positive evidence 
to the effect that the Greeks and Romans 
were acquainted with the idea of the 
transmutation of metals, — that is to say, 
with a belief in the production of pre- 
cious, from base metals. A passage in 
the works of Pliny, Historia 7iaturalis^ 
has, however, often been interpreted to 
this effect. Even the works of Homer 
have by some been thought to hold 
alchemistic teachings and wisdom. 

The oldest manuscript on chemistry, 
known at the present time, is a papyrus 
preserved at the University of Leyden. 
This papyrus is a book consisting of 
twenty leaves. Eight of these — that is 
to sa}'-, sixteen pages — are covered with 

4 



beautiful and most legible writing- in 
unical characters. 

This papyrus came from Thebes, in 
Upper Egypt, and is believed to have 
been made in the fourth century of our 
era, if not at an earlier period. It con- 
sists of a collection of one hundred and 
one precepts, many of these bearing on 
the chemistry of the metals. It appears 
to be an abstract made of other works, for 
it frequently gives several methods for 
the accomplishment of a given purpose. 
A Latin translation of this document, by 
Leemans, appeared in 1885; a French 
version of the same was published by 
Berthelot. 

As to the origin and meaning of the Origin. 
term chemistry, chimia^ in the form of °^^^^ 
scie7itiam chiniiae, occurs for the first time Chem- 
in the writings of Julius Maternus Fir- ^^ ^^ 
micus, who lived in the first half of the 
fourth century. It is, however, open to 
question whether the word was by him 
used in the sense and as having the 
meaning which attached to it later. In 
some of the earlier editions of the astrol- 
ogy of Firmicus, entitled Mathcsis, not- 
ably in the one printed in 1497, the 
expression is given, not as chimiac, but 
with the Arabic prefix, as alchimiac, 
5 



Zosimos uses the word chema for the 
knowledge imparted to man by superior 
beings, and employ's the term chemia 
apparently for designating the art of 
producing metals. 

The earliest Greek manuscripts which 
deal with these subjects rarely use the 
expression chemia^ but, instead, refer to 
the art of coloring, the art of making 
gold, the art of philosophy, and the 
sacred or divine art. 

The origin of this term has given rise 
to much stud}^ and comment. It has 
been held to have been derived from the 
Egyptian, the Arabic and the Greek, and 
various roots in these several languages 
have been assigned the role of its sponsor. 

Plutarch, in the second half of the first 
century, states in his work, Isis and 
Osiris, that the priests of Egypt desig- 
nated that country as Chemia, because of 
its black soil. The black part of the eye, 
the pupil, was also known by this same 
term. 

It has been suggested that the word 
has been derived from the Arabic word 
kema, which means hiding, secreting, and 
that the word al-kimija, Arabic for chem- 
istry, therefore originally signified the 
knowledge of the hidden, or the secret 
6 



art. The Arabians, however, primarily 
designated by this word a preparation 
made from the philosopher's stone, which 
could bring about a transmutation of 
other metals into gold or silver. 

Other writers have maintained that the 
term was coined from the name of an 
Egyptian king, Chemmis. In Sanscrit, 
kema means gold, and the possibility of 
a derivation of the word chemia from this 
root has not been left unnoticed. 

The word has also been written as 
chymia and as chimia^ and attempts have 
been made to trace its derivation to the 
Greek chymos, fluid or sap; it being in- 
ferred that the term was intended to 
indicate the art of working wnth solu- 
tions. 

Before the fourth century of the pre- Early 
sent era, chemistry, in the sense of a J^af"^" 
science, did not exist. Up to that time Knowl- 
no attempts had been made to collate ^ ^^ 
known facts, or to pursue the study of 
natural phenomena for the attainment of 
any one definite aim or purpose. 

The oldest races of man of whom 
records have been preserved, were in 
possession of more or less knowledge of 
a chemical nature, all of which, however, 
had been empirically acquired. 

7 



Knowledge of metallurgical processes- 
dates back to the very earliest of times. 
The originating of these arts and opera- 
tions was, by most nations, ascribed to 
their gods or heroes, and, in nearly all 
instances, a certain acquaintance with 
the working of metals will be found to be 
coeval with the beginnings of a nation's 
history. 

The Egyptians, Phoenicians, Greeks 
and Romans were among the nations 
possessing empirical knowledge of certain 
chemical facts and processes. With the" 
Egyptians the natural sciences were 
taught in the temples, by their priests. 
This knowledge was carefully guarded 
and the cult was shrouded in mystery. 
It is not impossible that the Egyptians 
had some conception of chemistry as a 
science, but the evidence to this effect is 
by no means conclusive. 

In the days of Homer, about looo b.c.^ 
the Greeks regarded iron as a most pre- 
cious metal ; this would indicate that at 
that time the Greeks could not have been 
possessed of a very extensive metallur- 
gical knowledge. 

Pliny is authority for the story, that 
once Tiberius was offered a cup wrought 
of a beautiful metal ; this metal was 
8 



lighter than silver, but closely resem- 
bled the same in appearance. I^earnin^ 
that the metal of which the cup was 
made had been obtained from clay, and 
that no one save its maker knew the 
process of its extracting, Tiberius had 
the unfortunate man destroyed, so that 
his secret should perish with him and 
that a depreciation of the precious metals, 
which might have been caused by this 
newly found material, might be avoided. 
More than eighteen centuries passed by 
ere the soft lustre of aluminium was again, 
beheld by the eyes of man. 

The art of dyeing was known to the 
Egyptians, the Phoenicians, the Greeks 
and the Romans. In the manufacture of" 
pottery the Egyptians excelled ; they 
sometimes glazed their bricks and used 
colored enamel in the decorating of finer 
pieces of pottery. The making of glass 
was probably also an invention of the 
Egyptians, notwithstanding that popular 
belief ascribes the discovery of this art 
to the Phoenicians. The sons of * ' the 
black soil ' ' furthermore possessed a 
knowledge of embalming, being familiar 
with the use of certain chemicals which 
arrested the decay of organic tissue. 

The preparation of various beverages 

9 



by fermentation was also known in those 

early times, — the mead of which old 

Norseland sagas have so much to tell,, 

was thus made from honey. 

^arly The ancients did not possess much 

of knowledge of Nature which was based 

^^^"T*^ upon observation and experimental in- 
Philo- ^ . . . , ^ , . 

sophy vestigation. As a rule, their natural 

philosophy was purely speculative, al- 
though there were some thinkers iu 
those times who were as keen in ob- 
serving as in reasoning. 

Most of these philosophers, however, 
took some assumption to be true and 
then endeavored to reason out conclu- 
sions from their premises. That their 
conclusions were often not only at vari- 
ance with the truth, but diametrically 
opposed to it, may be easily imagined. 
While the fact is well known that specu- 
lations concerning the ultimate particles 
of the primary constituents of the uni- 
verse were indulged in in very early 
times, it must be clearly understood 
that such speculations of the early philo- 
sophers were entirely distinct from, and 
independent of, any knowledge of chem- 
ical facts possessed at the time. 

Having given a passing glance at some 
of the chemical data in possession of 



the ancients, it may be of interest to con- 
sider briefly the views entertained by 
them in respect to the nature and the 
constitution of matter. 

The oldest teachings of India held that 
the world was made of wind, water, 
earth, fire and ether. Air, water, earth 
and fire, the four so-called ''elements," 
were by Empedocles of Agrigent re- 
garded as the basis of the world. About 
the fifth century before our era, Demo- 
critus of Abdera assumed the existence of 
a primal form of matter. This he ima- 
gined to be made up of the smallest 
possible particles, which differed from 
one another in form and size, but not in 
the nature of their substance. These 
particles were supposed to be in a state 
of continuous motion, forever entering 
into combinations, which combinations 
anon suffered disintegration. 

Aristotle, a pupil of Plato and the Philo- 
preceptor of Alexander, son of Philip of ^nstotle 
Macedon, was the author of a system of 
philosophy which has endured longer 
than any other system of philosophy the 
world has ever known. Even in the 
middle ages his views held dominance 
and w^ere regarded as the embodiment of 
all knowledge and truth. He considered 
II 



the properties of bodies to be the result of 
the simultaneous occurrence and inter- 
mingling of certain fundamental condi-^ 
tions ; his teachings regarded component 
elements only in the sense of bearers of 
these fundamental properties. Aristotle 
was far from looking upon the elements as 
ultimate particles the existence of which 
could be demonstrated and through the 
combination of which all bodies of the 
universe were formed. 

The primary qualities, in his opinion, 
were those which were perceptible to the 
sense of touch — for instance, warm, cold, 
dry, moist, heavy, light, hard, etc. Of 
these, he recognized the first four as the 
.fundamental properties, partly because 
the other properties were not so common, 
and partly because they could be re- 
garded as secondary phenomena caused 
by combinations of some of the former. 
He assumed that each element was en- 
dowed with two fundamental qualities, 
and as one and the same element could 
not, at the same time, have two antagon- 
istic properties, — could not, for instance, 
be both wet and dry, — only four com- 
binations were possible. The four ele- 
mentary conditions of matter he dis- 
tinguished were : fire (simultaneous 



dryness and heat), air (heat and damp- 
ness), water (cold and dampness), and 
earth (cold and dryness). In addition 
to these, this sage assumed the existence 
of a fifth element. This was rather of 
a more ethereal nature, and was termed 
* * Essentia. ' ' The Arabians accepted the 
doctrines of Aristotle about the sixth 
century, and up to the sixteenth century 
the teachings of his school claimed as 
devoted believers and adherents most 
scholars of all nations. 

The simpler substances into which Teach- 
complex substances could be resolved q^^Jj^ 
were, by the scholastics, termed elements. Schol- 
Non-decomposibility and the possibility *^ ^^* 
of suffering transmutation were regarded 
as properties common to all elements. 
The latter quality was held to be de- 
pendant on the similarity of the funda- 
mental properties of the elements be- 
lieved to be transmutable. As Aristotle 
taught, each element was possessed of 
two properties, one in a greater, the 
other in a less degree. Owing to the 
preponderance of some one property 
which two elements had in common, one 
element could readily be transformed 
into the other. Thus, air was warm and 
damp, water was damp and cold ; hence, 
13 



air could be transformed into water, and 
water into air. 

Density was considered as the result of 
cold, which caused the particles of a body- 
to approach close to each other. Poros- 
ity was regarded as the effect of warmth; 
hardness as the result of dryness; soft- 
ness was believed to be produced by 
dampness, and so forth. 

Again, the elements were classified as 
light and heavy. The former were fire 
and air; of these, fire was the absolutely, 
air the relatively, light element. Water 
and earth were the heavy elements; water 
the relatively, and earth the absolutely, 
heavy element. 
Belief Given such views and doctrines, it is 
Tmn^s- ^^^ difficult to understand that the most 
mutation marvelous tales of transformations and 
Matter transmutations could gain general cre- 
dence. Water, from the earliest times, 
was looked upon as a simple, undecom- 
posable form of matter. The Egyptians 
and the inhabitants of India regarded it 
as the fundamental substance from which 
many, if not all, other substances had 
been produced. 

Thales, in Greece, about 600 B.C., thus 
taught, and Aristotle, as has been pre- 
viously mentioned, considered water one 
14 



of the elements. Pliny ascribed the 
creation of water, the forming of clouds, 
to the condensation of air ; air — that is 
to say, wind — was believed to be pro- 
duced from water. 

Crystalline quartz was supposed to 
consist of water. Diodor, about 30 B.C., 
held that it was formed from the purest 
of water by the action of divine fire. 
The Greeks called quartz krystallos^ 
which signifies ice, and thus indicated 
their belief that quartz was formed 
from water — not, however, through 
the agency of fire, but through long- 
continued cold. Pliny, Seneca and others 
also bear testimony to this effect. 

Agricola, in the sixteenth century, was 
probably the first to dispute this asser- 
tion ; he suggested that if crystalline 
quartz be made from water, in the man- 
ner suggested — that is, as ice is formed — • 
then it too, like ice, should be lighter 
than water, and should be capable, like 
ice, of floating upon water. These views 
of Agricola found some supporters, still, 
belief in the possibility of the transmuta- 
tion of water into stone or into earth was 
seriously discussed in Europe, even by 
eminent experimentators, but little more 
than one hundred years ago. 
15 



Alchemy The origin of alchemy is undoubtedly 
to be sought for in remote antiquity. 
The legendary lore of the subject — tales 
of fair temptresses and of fallen angels, 
the story of the golden fleece and other 
traditions — have been previously re- 
counted. 

Most alchemists agreed upon Egypt as 
having been the home of their art, and 
acknowledged Hermes Trismegistos as 
one of the earliest masters, if not as the 
originator of their creed and craft. It 
seems impossible to determine the indi- 
4 viduality of Hermes — if, indeed, he does 

not prove to have been but a purely 
mythical creation. However that may 
be, his name occurs frequently in al- 
chemistic treatises which were written 
later than the fourth century. 

In the eleventh century, an alchemist, 
Hortulanus, made public a I^atin version 
of a brief essay which he ascribed to 
Hermes, and which came to be known as 
the tabula smaragdina. It is not known 
in what language this precept was origin- 
ally composed, but it is probably one of 
the earliest of alchemistic writings. The 
I^atin version of Hortulanus, as given by 
Kopp in his Geschichte der Chemiey is 
here reproduced and is followed by an 
i6 



English translation, for which the writer 
is indebted to a kind and learned friend. 

TABULA SMARAGDINA. 

Verum est sine mendacio, certum et verissi- 
mum : Quod est inferius est sicut id quod est 
:superius. Et quod est superius est sicut id 
quod est inferius, ad perpetranda miracula rei 
unius. 

Et sicut res omnes fuerunt ab uno, medita- 
tione unius : sic omnes res natae fuerunt ab 
hac una re, adoptione. 

Pater ejus est Sol, mater ejus est Luna. Porta- 
Tit illud ventus in ventre suo. Nutrix ejus 
terra est. Pater omnis telesmi totius mundi est 
hie. Virtus ejus integra est, si versa fuerit in 
terram. 

Separabis terram ab igne, subtile a spisso, 
^uaviter, magno cum ingenio. Ascendit a 
terra in coelum, iterumque descendit in terram, 
•et recipit vim superiorum et inferiorum. 

Sic habebis gloriam totius mundi. Ideo 
fugiet a te omnis obscuritas. 

Haec est totius fortitudinis fortitudo fortis, 
quia vincet omnem rem subtilem, omnemque 
solidam penetrabit. 

Sic mundus creatus est. 

Hinc erunt adaptationes mirabiles, quarum 
modus est hie. 

Itaque vocatus sum Hermes Trismegistus, 
habens tres partes Philosophiae totius mundi. 

Completum est, quod dixi de operatione 
5olis. 

THE EMERALD TABLET. 

True it is without a lie, sure and most true ; 

17 



what is below is like that which is above. And 
what is above is like that which is below, of one 
substance to perform miracles. 

And as all things have come from one being, 
the meditation of one, so all things have been 
generated from this one thing by adoption. 

Its father is the sun, its mother is the moon. 
The wind has carried it in its womb. Its nurse 
is the earth. The father of every talisman of 
the whole world is this. Its power is unim- 
paired when it is turned upon the earth. 

Separate the earth from the fire, the subtile 
from the material, gently, with great clever- 
ness. It rises from earth to heaven and again 
descends upon earth, and receives the force of 
those above and those below. 

Thus thou wilt have the glory of the whole 
world. All obscurity, therefore, will leave 
thee. 

This is of all strength the strong strength, be- 
c .use it will subdue every subtile thing and 
penetrate every solid. 

Thus has the world been created. Hence 
there will be wonderful adoptions whose 
measure is this. 

Therefore I have been called Hermes Tris- 
megistus, possessing three parts of the philo- 
sophy of the whole world. 

What I have said of the operation of the sun 
has been fulfilled. 

x\nd the meaning of this word- jungle 
through which reason vainly seeks to 
blaze a trail? Ah, — **that is another 
story." 

i8 



The earliest piece of historical evidence Trans- 
which can be adduced in support of the of Metals 
claim that attempts were made to obtain 
gold and silver from alien substances, 
dates back to the fourth century. 
Themistos Euphrades, a Grecian orator 
of the time, refers to the transmutation 
of copper into silver and of silver into 
gold as well known facts. But the first 
indisputable record of belief in the trans- 
mutation of silver, tin and copper into 
gold, occurs toward the end of the fifth 
century, in the writings of Aeneas 
Gazaeos, a native of Syria. 

As Kopp has well pointed out, it is 
not unlikely that in those early times a 
covering or plating of gold or silver may 
have been regarded as an actual trans- 
mutation of the gilded or silvered objects 
into the precious metal. 

It was probably the production of al- 
loys having the color of gold or of silver, 
that first led to a belief in the possibility 
of transmutation. An alloy of copper 
with an impure oxide of zinc exhibits a 
yellow color ; copper with arsenic yields 
a silvery white compound ; mercury and 
lead form an amalgam which could easily 
be, and was, mistaken for tin. 

Obtaining silver from a lead ore, in 

19 



which it occurred naturally, was, by the 
alchemists, regarded as proof that a pre- 
cious metal could be produced from a 
base metal by transmutation. The de- 
position of metallic copper on iron, when 
this was inserted in a solution of some 
copper salt, w^as considered a case of 
conversion of iron into copper. Distilla- 
tion of a gold or silver amalgam which 
resulted in the securing of the precious 
metal and the loss, by volatilization, of 
the mercury was, by the earlier alche- 
mists, taken as a proof of the creation of 
the metal which remained in their hands 
after completion of the process. 

Alchemy, therefore, most likely had 
its origin in a misconception and misun- 
derstanding of phenomena imperfectly 
observed. 
Spread Egypt was certainly , the home of 
Alchemy ^^chemistic learning during the first 
centuries of the present chronology. 
Alexandria with its high-school, de- 
stroyed in 642, formed the central station 
where adepts prosecuted and taught their 
mysterious cult. 

A new era for alchemy began with the 

conquest of Egypt by the Arabians in 

the year 640. The conquerors soon came 

to realize that a mere simulation of color 

20 



in alloys did not make gold and silver of 
those alloys. They, however, firmly be- 
lieved that a complete transmutation of 
one metal into another could be effected, 
and the achievement of this end formed 
the goal of their ambition and endeavor. 

Knowledge of alchemy — the Greek 
term chemia to w^hich the Arabic article 
was prefixed — was carried by the Ara- 
bians to Spain, which country they en- 
tered in or about 711, after having 
passed through northern Africa. From 
Spain alchemy spread over western Eu- 
rope ; in the thirteenth century the 
Hermetic art, or the art of the sun, as 
alchemy was also termed, had its adhe- 
rents, the so-called adepts, in Germany, 
France and England. The two following 
centuries witnessed extension of the art 
in other parts of the w^orld, but also 
initiated its decadence in Spain. 

The original and principal aim of Aims of 
alchemy was the production of a sub- -^^^^^^^y 
stance w^hich was variously designated as 
the philosopher's stone, the great elixir, 
the great magisterium, and the red 
tincture. 

This material was supposed to have 
the power of transmuting base metals 
into gold, — in fact, of creating gold, for a 
21 



small quantity of the philosopher's stone 
was believed to suffice to produce large 
quantities of the precious metal. 

There seems to have been a consider- 
able difference of opinion among the. 
adepts as to the extent and the powers 
of this medium. Some held that it could 
transform every base metal and any 
amount of it into gold ; others, that in a 
less perfect condition it could transform 
only a limited amount of some certain 
base metal. 

Some of the earlier alchemists distin- 
guished between a great and a smalL 
elixir, or a red and a white tincture. 
The former of these was deemed capable 
of accomplishing the transmutation of 
base metals into gold, the latter of effect- 
ing their transformation into silver only. 
Manu- Directions for making the philosopher' s 

of the stone are numerous and varied, and often 
Philoso- mutually contradictory. 

Stone To outline the process in a general 
way, it appears that, naturally, the first 
requisite was the securing of the crude 
material to be used. This substance was 
known as materia prima criida^ as terra 
virginea^ and by various other terms, and 
the obtaining of this substance was re- 
garded as the most difficult part of the 



whole undertaking. '^11 n'y a que le 
premier pas quicoute/* — as the French 
have It. Although it was believed to 
occur in great quantities, its identity was 
unknown to the workers and the search 
for this substance extended to and 
through almost all things under the 
heavens. 

From this materia prima cruda there 
was to be obtained the 7nateria prima 
matura^ also designated as mercurius phi- 
losophorum^ chaos, azoth, etc a sub- 
stance in which the principles of mercury 
and of sulphur were believed to be con- 
tained in the state of greatest purity. 

To this mercuriiis philosophoruvi there 
was then to be added aitro philosophorum, 
philosopher's gold, and this mixture, 
carefully guarded from the air, was 
digested at a low heat for a considerable 
length of time. This operation was car- 
ried on in the ovum philosophiaim^ a 
vessel of a form carefully prescribed. As 
a result of this proceeding, which the 
alchemists termed cineration, corruption, 
or the death of matter, a black body was 
obtained — \h^ caput corvi , or raven's head. 

Through continued digestion, termed 
albification , puri fication , resurrection , 
this black substance became transformed 
23 



into a white body — the swan. When, 
this latter had been secured, the temper- 
ature to which it was exposed was raised;: 
the substance turned yellow and finally^ 
a brilliant red. And then — Behold! the 
philosopher's stone in its greatest per- 
fection ! 
Descrip- -^he descriptions of the appearance of 
the Phil- "the great magisterium differ widely, as 

osopher's given by various alchemists. By some it 
Stone 

was spoken of as a red powder, by others 

it was said to possess a peach-blow color; 
others still affirmed it to be of grey ap- 
pearance. Paracelsus, in the sixteenth 
century, described it as a very stable 
substance, red as a ruby and transparent 
as crystal, pliable as gum, and yet fragile 
as glass. In the powdered state, it was- 
said to resemble saffron. 

As to the amount of the substance 
which was to be used in order to trans- 
mute a given quantity of base metal into 
gold, the statements also differ mate- 
rially. The more perfect the philoso- 
pher's stone, the less of it, it seems, was 
required. Roger Bacon stated, that one 
part of this substance could transmute 
one million parts of base metal. From 
this statement down the estimates vary, 
until one adept, Kunkel, in the latter 
24 



part of the seventeenth century, modestly 
claims that one part of the philosopher's 
stone can transmute but two parts of 
base metal. 

Belief in the possibility of transmuta- 
tion was, as previously indicated, orig- 
inally based upon the view held 
with regard to the constitutions of the 
metals. All metals were believed to be 
compounds, and were regarded as being 
composed of two substances which varied 
in amount and in degree of purity; these 
factors determined the nature of the 
metal. The names assigned to these 
two substances were mercury and sul- 
phur, but these terms were used, not to 
denote the elements which are now so 
called, but they must rather be regarded 
as standing for the conceptions of certain 
properties. Under the term viercurius^ the 
alchemists seem to have understood the 
idea of the non-decomposible; they saw 
in this constituent the cause of metallic 
glance and of malleability. The term sul- 
phur was used by them to express the idea 
of transmutability and of combustibility. 
DifEerent metals w^ere regarded as com- 
pounds of these two substances in differ- 
ent proportions. Gold, for instance, was 
regarded as a compound of much mer- 

25 



cury with but little sulphur, but both iix 
the state of greatest purity and in firm- 
combination. 

Basing then on the conception that, 
other metals differed from gold solely irt 
the proportions in which these constitu« 
ents, mercury and sulphur, were present, 
it seemed not unreasonable to seek for an 
agent whereby these proportions could 
be readjusted and gold produced. 
Powers In the course of time other wonderful 
Ph?loso- properties, besides the power of effecting 
pher's the transmutation of metals, came to be 
^^°"^ ascribed to the philosopher's stone. For 
instance, it was reputed to have the 
power of curing all ills that flesh is heir to. 
Thus, Faust, in Bayard Taylor's mas- 
terly translation of Goethe's classic: 

** My father's was a sombre, brooding brain, 

Which through the holy spheres of Nature 
groped and wandered, 

And honestly, in his own fashion, pondered 
With labour whimsical, and pain: 

Who, in his dusky workshop bending, 
With proved adepts in company, 

Made, from his recipes unending. 
Opposing substances agree. 

There was a Lion red, a woer daring. 
Within the Lily's tepid bath espoused. 

And both, tormented then by flame unsparing^ 
By turns in either bridal chamber housed. 

If then appeared, with colours splendid, 
The young Queen in her crystal shell, 

This was the medicine "... 
26 



This medicine was styled '^ the great 
panacea/' and it was claimed by some of 
the adepts that its possession would con- 
fer eternal youth and life on its favored 
owner. 

This belief in its powers, however, 
does not occur before the eighth century 
and probably crept into existence gradu- 
ally owing to Europeans attaching too 
literal a meaning to some of the earlier 
descriptions of its properties, given, at 
times, by the Arabians, with all the 
splendor of Oriental imagery. . Thus,. 
Geber termed the base metals invalids 
which he would cure, that is, transmute,. 
by aid of the philosopher's stone ; others 
wrote of curing through its help the 
dread evil — poverty. A misconception 
of the kind indicated could thus have 
arisen very easily, and having once been 
formed, would naturally but serve to 
stimulate the zeal of the adepts in pur- 
suit of their life's quest. 

Another object which some alchemists 
sought to attain was the making of lamps 
that would burn forever ; gold in the 
liquid state was reported to be the 
principal ingredient of the fluid which 
w^as to furnish the perpetual light. 
Belief in the existence of such lamps 
27 



was prevalent in the sixteenth and in the 
seventeenth centuries, and quaint and 
curious are the legends which tell of 
such wondrous lamps having been found- 
burning in tombs and sepulchres, but 
which were instantly extinguished on 
coming into contact with air. 

About the year 1600, a German phy- 
sician, one of the most eminent alchem- 
ists of his time, claimed that the philoso- 
pher's stone could transform quartz into 
gems, could change a thousand pearls- 
into one pearl of exquisite beauty and 
could render glass malleable. Even the 
imparting of moral culture, redemption 
from sin and evil, was believed to lie 
within the power of this magic substance. 
Sendivogius, about the commencement of 
the seventeenth century, considered the 
philosopher's stone to be a mirror and 
claimed that he who possessed it could, 
on peering into the same, behold therein 
three parts of the wisdom of the whole 
world and thus would grow to be as wise 
as Aristotle and Avicenna. 

But it would be idle and lead too far 
to attempt here a recounting of the many 
marvelous tales of miracles of various 
kinds said to have been accomplished by^ 
the aid of this agent of agents. 
28 



The story — and Finis has not even now, 
at the end of the 19th century, been 
written beneath the final chapter, — is one 
of intense human interest. On the one 
hand, one finds most unselfish devotion 
and self-sacrifice in the pursuit of an 
impossible ideal; on the other, a sinking 
to the lowest depths of deception, fraud 
and infamy. 

Turning the broad and well-worn 
pages of some ponderous old tome on 
this occult art, — written perchance cen- 
turies ago and heavy with the dust of 
ages, — one seems transported into a realm 
of magic and necromancy. Mysterious 
symbols alternate with equally myste- 
rious and unintelligible directions for the 
guidance of the seeker after knowledge. 
We of to-day who examine these writ- 
ings in the clear, calm light which 
Science sheds on their pages, may won- 
der at the power which has been theirs 
to hold even master-minds in bondage, — 
a Newton and a Leibnitz were not above 
their magic spell, — but still we cannot 
repress a feeling of compassion and of 
regret for those unnumbered thousands, 
whose hopes were foreordained to dis- 
appointment, whose struggles were fore- 
doomed to failure, but who, notwith- 
29 



standing, pursued to the bitter end the 
luring glitter of the phantom gold. 
latro- l^he sixteenth century witnessed the 
istry differentiation of chemistry from alchemy. 
While alchemy of course continued to 
claim numerous adepts, other interests 
began to attract the attention of many 
students of natural science. 

The belief that chemistry should serve 
the interests of medicine, became the 
guiding star of our science during the 
next epoch of its development. But here 
and there work of a chemical nature was 
done also in other directions. One per- 
sonage who comes rather prominently 
into view at this time is Georg Agricola, 
a German, who may be said to occupy a 
position of his own in a time the chief 
trend of which was towards the healing 
art. 

Agricola, although a physician, can 
perhaps best be described as an industrial 
chemist. He gave his attention largely 
to the study of metallurgy and industrial 
pursuits and in 1546 embodied his knowl- 
edge of metallurgical processes in a work 
entitled : Libri XII de re metallica. 

It was Paracelsus, or, to give him the 
full benefit of his name, Phillippus 
Aureolus Theophrastus Paracelsus Bom- 
30 



bastus von Hohenheim, who asserted 
that medicine was but chemistry ap- 
plied, and it was mainly through his 
labors and his influence that chemistry 
and medicine came to be regarded 
as so closely allied. Under his guid- 
ance and that of his followers, the 
guardianship of chemistry passed more 
and more into the hands of physi- 
cians. The new departure thus initiated 
by Paracelsus and his disciples, of whom 
Van Helmont and Franz de le Boe 
Sylvius were the most distinguished, is 
generally known as the period of iatro- 
chemistry. 

During this epoch it was commonly 
believed that health as well as sickness 
was dependent on chemical processes. 
Normal physiological phenomena, the 
conditions of life in its usual state, were 
regarded as chemical functions in which, 
the active constituents reacted on one 
another in proper proportion. Patho- 
logical phenomena were held to depend 
upon a disturbance of these normal pro- 
cesses; one or another of the constituents 
predominated unduly ; in short, disease 
was regarded as an abnormal chemical 
process and therapeutics was charged 
with the task of neutralizing, by chem- 

31 



ical means, such constituents as might be 
present in excess. 

It is Van Helmont who should be 
credited with being the first to suggest 
the rudiments of chemical physiolog3^ 
He searched for the actual substances in 
organic matter, and compared the re- 
action of various juices which mingle 
wath one another in the organs, to the 
action of such juices outside of the 
organs. His views on the constitution 
of matter were of great importance to 
chemistry, for he was the first to for- 
mally denounce the theory of Aristotle, 
and to demonstrate that fire is no 
element. 

He also declined to accept the theory 
of Paracelsus, that all metals consisted 
of mercury, sulphur and salt, — terms, of 
course, used in a sense different from that 
which now attaches to the same. Van 
Helmont was also the first to announce, 
that in the formation of chemical com- 
pounds, the original substances remain, 
although they may undergo chemical 
changes. This claim probably heralds 
the first dawn of that important and 
brilliant conception — the indestructibility 
of matter. 

Van Helmont regarded water as the 
32 



primal principle of all matter. That it was 
present in organic substances, he inferred 
from invariably finding it as a product of 
combustion of organic bodies. He be- 
lieved in the transformation of water 
into earthy matter, and in proof of his 
assertion adduced the fact, that a tree 
which he had planted in a weighed 
amount of soil and which was watered 
carefully for five years with rain and 
distilled water, had experienced a gain 
of one hundred and sixty-four pounds, 
while the soil in which it had been 
grown had lost but a couple of ounces 
in weight. Van Helmont also gave con- 
siderable attention to the study of gases, 
and described carbonic acid gas, a pro- 
duct of fermentation ; he named it gaz- 
sylvestre. 

In his eyes, the noblest aim to which 
chemistry could aspire was the discovery 
of a universal solvent, for it was held 
that substances could not experience 
chemical changes unless they were in a 
state of solution. This same ideal sub- 
stance should also act as a universal 
medicine; it was designated as the men- 
struuin universale^ or the alkahest. Its 
preparation was depicted as the crowning 
glory of chemical achievement. 

33 



Andreas Libavius, although a believer 
in the main tenets of alchemy, contri- 
buted much to the progress of chemistry^ 
by his valuable discoveries and observa- 
tions. He pointed out many of the 
follies and errors of Paracelsus and his- 
school and was the first to collect in his 
writings all of the principal chemical 
facts which were then known. His 
treatise, Alchymia^ published in 1595, is 
regarded as the first text- and hand- 
book of chemistry. 

Among other men prominent in chem-^ 
ical science in those times there should 
be named Daniel Sennert and Johann 
Rudolph Glauber. Both were Germans. 
The latter has been regarded as one of 
the best chemists of his day. Otto 
Tachenius, a countryman of Sennert and 
of Glauber, and a devoted pupil and fol- 
lower of de le Boe Sylvius, made some 
valuable contributions to the knowledge 
cf the composition of chemical sub- 
stances. He originated the definition 
of the term salt: a compound of an acid 
and an alkali. He also studied the pro- 
portions by weight in which substances 
react chemically, and noted the increase 
in weight which takes place when lead 
is transformed into its oxide. 

34 



During this period of iatro-chemistry 
the interests of chemistry were served to 
good purpose, chiefly because its care 
was removed from the exclusive control 
of the alchemists and entrusted in great 
part to physicians, among whom were 
many men of education and culture. 
Chemical reactions and processes came 
to be carefully studied in order to secure 
explanations of observations made for 
medical purposes. New chemical com- 
pounds were prepared for use as drugs, 
and thus, gradually, the domain of 
chemical knowledge came to be enlarged, 
through painstaking research and ex- 
perimentation. 

Having contributed much to the 
general advancement of the science, it 
seems rather strange that the iatro-chem- 
ical theory should not have held sway 
longer. The cause of its passing must be 
sought principally in the endeavors made 
by its devotees to explain, from its one 
limited point of view, all processes and 
phenomena of life. 

As the study of vital processes, in 
health and in disease, became more 
general and more exact, adherents of 
the iatro-chemical school were driven to 
labored and oftentimes futile attempts at 

35 



explaining phenomena which were ob- 
served, and many of the claims they 
made could not be upheld when put to 
the test of practical experiment. 
Period By the middle of the seventeenth cen- 
9^ tury, thanks to the endeavors of the 
tion alchemists and the labors of the iatro- 
chemists, knowledge of a great number 
of chemical facts had been amassed. 
The metals had been well studied; the 
action of heat upon many substances, 
organic and inorganic, had been ob^ 
served; a knowledge of many salts, com- 
pounds of the alkalies with the mineral 
acids, had been obtained, and the time 
had come for an attempt at collating the 
numerous isolated facts and phenomena 
which were known. 

The new era which was soon to dawn 
for chemistry, — chemistry as a science, — 
was foreshadowed at this time by the 
great Englishman, Francis Bacon of 
Verulam. Bacon was born in London 
in 1561 ; he was Lord-Chancellor of 
England in 1619, and died in 1626. 

He taught, that truth in the experi- 
mental sciences may be ascertained only 
by progressive generalization — starting 
from some fact or principle most care- 
fully and accurately ascertained. Each 
36 



new step must be supported by experi- 
mental evidence and proof. Only in 
this manner, he pointed out, may general 
laws be deduced and discovered. The 
<:orrectness of such laws, in their turn, 
must be proven and demonstrated by 
their accounting for each and every 
detail of all phenomena on which they 
hear. 

Another man whose studies and re- 
searches, dictated by a love of science 
for science' sake, proved of the utmost 
value for the progress of chemistry, was 
Robert Boyle. He followed the example 
pointed out by Bacon of Verulam, mak- 
ing experiments the proof and touchstone 
of his statements. Boyle is regarded as 
the founder of analytical chemistry, 
being the first to introduce analysis in 
the wet way. He contributed a great 
number of valuable data to physics as 
well as to chemistry, and was opposed to 
most of the teachings of alchemy as well 
as to the claims of iatro-chemistry. 

He demonstrated that neither the four 
elements of Aristotle, fire, water, air and 
earth, nor those of the alchemists, salt, 
sulphur and mercury, could be regarded 
as the elements of chemistry. He did 
not advance any definite chemical theory 
37 



Tiimself, — indeed, there were in his time 
not sufi&cient well established data to 
Tvarrant such procedure, — but he rather 
devoted his time and talents to enriching 
the chemical and physical knowledge of 
his day by numerous well planned and 
carefully executed researches. 

He was, for instance, familiar with the 
fact that air contains something which is 
consumed by breathing and by com- 
bustion. He confirmed the observation 
made in 1630, by Jean Rey, a physician 
of Perigord, that metals, when calcined 
in air, increase in weight. Boyle, more- 
over, noticed that when lead is trans- 
formed into litharge, in a confined and 
known volume of air, that the volume of 
this air is diminished in the process. 
He, however, did not perceive the true 
cause of this fact, — the absorption of the 
oxygen of the air by the lead, but at- 
tributed the increase in weight the 
material experienced, to the absorption 
of a ponderable heat-substance, which, 
in his opinion, united with the lead 
during the calcination. 

Boyle's activity extended to almost all 

branches of chemistry. Perhaps his 

most important work — and his writings 

fill six quarto volumes — was : ' ' The 

38 



Sceptical Chymist or Che7nicO' physical 
Doubts arid Paradoxes^ touching the Ex- 
periments whereby vulgar Spagyrists are 
wont to endeavor to evince their Salt, Sul- 
phur, Mercury, to be the true Priiiciples 
of Things,'' This book was published 
in 1661. 

In 1665 an English chemist, Hooke, Theory 
published a work, Micrographia, in co^bus- 
which he discussed the similar behavior tion by 
of air and of saltpetre in the supporting ^'^^ ^ 
of combustion. He concluded, that com- Mayow 
bustion was effected by virtue of a con- 
stituent which was present in both air 
and saltpetre. 

The completion of Hooke' s theory was 
effected by John Mayow, who pointed 
out in a paper, De Sale Nitro et Spiritu 
Nitro-aereo, published in 1669, that the 
supporting principle of combustion is 
the spiritus nitro-aerens (oxygen) com- 
mon to both air and the nitre. He 
also inquired into the phenomena of 
respiration and decided that this pro- 
cess was analogous to the process of 
combustion. 

But the views of Hooke and Mayow, 
notwithstanding the fact that they were 
logical conclusions drawn from experi- 
ments carefully made, did not meet with 

39 



general appreciation nor acceptance by 

their contemporaries. 

Pounda- The conception that the process of 

of the combustion is a process of decomposition 

Phlo- had been entertained since the earliest 

-]^eory times. When a substance is burned, a 

something, appearing to the beholder as 

flame, escapes from the burning body. 

That which remains after combustion 

came, quite naturally, to be regarded as 

another constituent of the body which 

had been burned. 

If the experiment made by Boyle, 
showing the increase in weight which 
metals experience on heating, had been 
correctly understood and interpreted, or, 
if the work of Hooke and Mayow had 
been rightly valued, it is probable that 
the theory which we are now called on 
to consider— the Phlogiston Theory — 
would never have been advanced, or, at 
least, would never have enjoyed the wide 
popularity to which it attained. 
Phlo- This theory was originally advanced 
'Hieo^y ^^ J- J- ^^^^^^ ^^^ materially elaborated 
by Georg Ernst Stahl. According to 
its teachings all combustible bodies are 
compounds. All inorganic, or, as Becher 
calls them, subterranean bodies, are of 
an earthy character and have as their 
40 



fundamental constituents combustible 
earth, terra ping ids , mercurial earth and 
vitrifiable earth. All compound bodies 
contain, in varying proportions, at least 
two of these. 

If metals are heated in the presence of 
air, the combustible principle escapes, 
and the non-combustible earth, the calx, 
remains. The property of undergoing 
combustion can therefore be possessed 
only by compound bodies. Substances 
not affected by fire, — quicklime, for in- 
stance, — were supposed to have already 
suffered combustion. The combustible 
substance, the terra piyiguis, is not a 
'' fire-matter," but only a principle, and 
it received from Stahl the name Phlogis- 
ton, from the Greek term for com- 
bustible. Phlogiston is thus the prin- 
ciple of combustibility. 

The phlogiston which escapes into the 
air is absorbed from the air by plants and 
passes from vegetable bodies into animal 
bodies. Bodies which contain phlogiston 
in great quantity. — coal, for instance, — 
also readily part with it ; calxes of metals 
heated with coal, take up phlogiston 
from the coal and are again transformed 
into the original metallic substance. 
The difference between various metals was 
41 



ascribed to the specific calx which each 
was supposed to contain. The colors of 
bodies were attributed to the phlogiston 
they possessed and variations in color 
were held to be due to changes in the 
quantity of phlogiston present. 

Stahl, in advancing the theory of 
phlogiston, did not seek to deny that 
metals increase in weight on calcination, 
although he claimed that they lost phlo- 
giston. He simply stated that phlogiston 
escaped on calcination, '^although" an 
increase of weight was noticeable ; he 
furthermore held that phlogiston was 
absorbed on reduction, ''although" a 
decrease in weight was to be observed. 
This simply illustrates that in the earlier 
part of this period no regard whatever 
was paid to quantitative relations. 

In Sweden, Torbern Bergman and 
Carl Wilhelm Scheele were about this 
time the most. noted chemists of their 
country. Bergman's merits were espec- 
ially great in the field of analytical 
chemistry ; the credit of having pointed 
out the ways followed to this day in the 
analysis of inorganic substances belongs, 
in a great measure, to him. He attempt- 
ed many investigations of a quantitative 
character and sought to determine the 
42 



amount of phlogiston in combination 
with various metals. 

Scheele, a friend of Bergman's, was a 
pharmacist in Gothenburg. In his 
leisure hours he faithfully studied the 
works of Lemery, Stahl and others, and 
devoted much time and labor to the 
carrying on of chemical experiments. 

His researches extended into the 
domains of both organic and inorganic 
chemistry. In the former field he gave 
much attention to the organic acids, in 
the latter he worked principally on man- 
ganese dioxide, chlorine, and baryta ; 
that solutions of baryum-salts can serve 
as delicate reagents for the detection of 
sulphuric acid, was a discovery made by 
him. He also published exhaustive in- 
vestigations on air and on fire, and, inde- 
pendently of others, discovered oxygen. 

Scheele was an outspoken adherent of 
the phlogiston theory, but his views were 
nevertheless materially different from 
those of Stahl, declaring phlogiston to be 
the principal constituent of light and of 
combustible air. 

It is quite possible — not to say prob- 
able — that both Scheele and Bergman 
would have abandoned the phlogiston 
theory if they had lived long enough 

43 



to v/itness the final phase of the con- 
troversy. 

Among the most eminent chemists of 
France there were, at this time, S. F. 
GeofEroy, J. Hellot, Duhamel du Mon- 
ceau, and P. J. Macquer. The latter, 
although he himself had executed quan- 
titative analyses of mineral waters and 
of other substances, utterly failed to see 
and to acknowledge the all-important 
bearing which quantitative relations had 
on the theory of phlogiston, a theory 
which he sought to defend to the best of 
his ability. 

Prominent among English supporters 
of the phlogiston theory were at one 
time. Black, Cavendish and Priestly. 

Henry Cavendish was an eminent 
English scientist, who, through his in- 
vestigations and experiments, forged the 
principal weapons which, in the hands of 
others, ultimately caused the destruction 
of the phlogiston theory. Yet he him- 
self remained an ardent adherent of its 
teachings to his end. In 1766, he recog- 
nized hydrogen to be a peculiar gas. 
He believed it to be pure phlogiston 
and thought that it was set free from 
metals by acids, because acids cause 
the destruction of metals. Nitrogen gas 
44 



lie believed to be air saturated with 
phlogiston, oxygen, to be air devoid of 
phlogiston. 

Joseph Priestly also remained to the 
end of his life a warm defender of the 
phlogiston theory. He accounted for 
the fact that air is necessary for com- 
bustion, by stating that phlogiston, if it 
is to be induced to leave a body, must 
find some other substance, air, to com- 
bine with. 

Priestley's most important discovery 
was made in 1774, when he prepared 
oxygen by heating red oxide of mercury. 
Although he learned that this gas sup- 
ports respiration and combustion more 
actively than air does, yet he did not ap- 
preciate the true role which oxygen plays 
in the process of combustion. 

At no time had the phlogiston theory, Deca- 
although so generally accepted, gone ^r^^^ 
unchallenged. Remonstrances against it Phlo- 
had been made, among others, by Boer- ^^^^^^ 
have, by Hoffmann and by Buff on. The 
latter even went so far as to express it as 
his conviction that phlogiston was rather 
more likely to exist in the minds of the 
adherents of the theory than elsewhere 
in nature. 

Joseph Black was an investigator of 
45- 



great originality and ability. He gave 
much attention to the preparation and the 
study of gases, a work in which he had 
many followers and which led to the 
designating of this epoch as that of 
pneumatic chemistry. He became a 
confirmed opponent of the phlogiston 
theory, although, for a long time, he had 
been one of its adherents. Contrary to- 
the teachings of this theory, he had early 
turned his attention to quantitative de- 
terminations, and readily perceived that 
it was of prime importance to study the 
weight relations in chemical processes, as 
these only could lead to an elucidation of 
reactions. 

By his masterly work on the alkaline 
carbonates, Black demonstrated that 
there was no such substance as phlo- 
giston, to the absorption of which the 
caustic properties these carbonates ac- 
quire on treatment with caustic lime 
was generally ascribed. 

He proved that non-caustic lime de- 
creases in weight on being rendered 
caustic through ignition, and showed 
that this loss in weight was accounted 
for by the liberation of '' fixed air '' 
(carbonic anhydride). 

But Black did not perceive the ultimate 
46 



logical sequences of his own discoveries. 
Notwithstanding his ingenious researches 
and their correct interpretation, it re- 
mained for another to collate all the facts 
and data and to effect therewith the 
overthrow of the Phlogiston theory. 

This man was Antoine Laurent Lavoi- Lavoi- 
sier. Born in Paris in 1743, he received ^^^ j^j^ 
an excellent education and training, Work 
especially in the mathematics and the 
natural sciences. 

His career was equally brilliant as a 
scientist and as a statesman. He lost 
his life on the scaffold in 1794, during 
the reign of terror in the French 
Revolution. 

So marked were his attainments and 
his services to chemistry, that an admir- 
ing compatriot of his, Adolphe Wurtz, 
wrote, but thirty years ago : '' La chimie 
est line science frangaise, Elle fut co^isti- 
tuee par Lavoisier^ d' immortelle memoire. ' ' 

Lavoisier was the founder of the anti- 
phlogistic theory and he was the first to 
correctly interpret the increase in weight 
which metals experience on undergoing 
combustion. He recognized that com- 
bustion is not a process of decomposition, 
as the phlogiston theory maintained, but 
that it is a process of combination. The 
47 



substance undergoing combustion com- 
bines with a certain substance contained 
in the air. 

Records dating from 1772 show that 
already at that time this question had 
occupied his attention. But it was only 
in 1775 that he enunciated his anti- 
phlogistic theory. 

He demonstrated that the amount by 
which the burned substance increased in 
weight was exactly equal to the weight of 
the gas absorbed. To quote his words : 
*'The whole is greater than its part ; 
the products of combustion, which are 
heavier than the combustible bodies, 
cannot therefore be the elements of the 
latter, for, in chemical reactions, nothing 
is lost, nothing is created, matter being 
indestructible. If bodies increase in 
weight by burning, it is by the gain or 
addition of a new substance ; when, on 
the other hand, metallic calxes or oxides 
are reduced to the metallic state, the 
effect is due, not to the restitution of 
phlogiston, but to the loss of the vital 
air which they contain." 

While the views of Lavoisier marked 

a great step in advance and, in fact, 

ushered in a new era in the history of 

chemical science, it must not be over- 

48 



looked, that the phlogiston theory had 
exercised a most wholesome influence on 
the evolution of chemistry. 

Following upon the period of storm 
and stress in which chemistry first at- 
tained to the dignity of an independent 
science, the phlogiston theory furnished 
the light by which chemistry, but newly 
freed from the fetters and bondage of 
alchemy and iatro-chemistry, was guided 
on her way. 

That this theory should, at first, have 
concerned itself only with qualitative 
phenomena must also be considered as in 
perfect keeping with the natural course 
of events. When it had taught these 
qualitative phenomena to be thoroughly 
understood and when attention came to 
be directed to the consideration of quan- 
titative relations, barriers were encount- 
ered which it could not surmount. 

I^avoisier first employed the term 
*' oxygen" in 1778. Prior to that time 
he referred to this gas as '' vital air,'^ or, 
as ' ^ the air eminently adapted for the 
supporting of combustion and respira- 
tion. '* Oxygen was then also known 
as ' * dephlogisticated air. ' ' 

In 1783, Lavoisier and Laplace re- 
peated the experiments of Cavendish 

49 



and verified the latter' s discovery of 
the compound nature of water. The 
experiment consisted in synthetically 
combining oxygen with hydrogen 
( ' ' phlogiston " ) . Knowledge of this 
fact permitted Lavoisier to give a clear 
explanation of the phenomena of the 
dissolving of metals in acids and of the 
combination of metals with oxygen 
during combustion. 

Lavoisier made numerous and careful 
researches in many directions ; he was 
great, not only in correctly making, but 
also in correctly interpreting the results 
obtained in experiment by himself and 
by others, results which were, often- 
times, not properly understood nor 
rightly valued by the very men who had 
obtained them. 

Having grasped the part which oxygen 
plays in the formation of acids, oxides 
and salts, he established a new. chemical 
theory, which supplanted the views for- 
merly held, and much of what we con- 
sider true in chemistry at the present 
time was first enunciated by him. 

The elementary nature of the metals 

was pointed out, and the general idea of 

*' simple" bodies was established. He 

defined an acid as resulting from the 

50 



union of a simple body, generally non- 
metallic, with oxygen. An oxide re- 
sulted from the union of a metal with 
oxygen. A salt was defined as being 
formed by the combination of an acid 
and an oxide. 

''Simple,*' that is to say, elementary, 
bodies were shown to possess the pro- 
perty of uniting to form compounds and 
the combination was shown to be effected 
without loss of matter. Binary com- 
pounds of the first order were formed by 
the union of two elementary bodies. 
Binary compounds of the second order 
were formed by the union of binary com- 
pounds of the first order. 

Of course, even this anti-phlogistic 
theory was not perfect and the constantly 
increasing advance of chemical knowl- 
edge soon presented instances and phe- 
nomena which this theory could not 
explain nor account for. Nevertheless, 
it was a masterly and broad conception, 
and like the phlogiston theory which it 
supplanted, it contributed, in its day, 
materially to the growth and the develop- 
ment of chemical science. 

Among the French chemists who 
avowed themselves followers of Lavoi- 
sier's teachings, were Guy ton de Mor- 
51 



veau, A. F. de Fourcroy, and Claude 
Ivouis BerthoUet. 

In Germany, M. H. Klaproth was the 
pioneer of the anti-phlogistic theory. 
There was a battle royal ere the adhe- 
rents of the theory advanced by Stahl 
and Becher surrendered to the standard 
bearers of the ''chimie frangaise," as 
Lavoisier's teachings had come to be 
known. General acceptance was not 
accorded these views in Germany until 
fully a decade after they had gained the 
day in France. 

It was at Klaproth's request, that the 
Berlin Academy, in 1792, subjected the 
whole question of combustion to a rigor- 
ous test; the results of this investigation, 
it is almost needless to say, fully con- 
firmed the statements of Lavoisier. 
Era of The precepts set by Lavoisier, the in- 
tative troduction of the balance as the decisive 
Investi- factor in chemical research, opened to 
^ chemistry a new era which has most 

appropriately been termed the era of 
quantitative investigation. 

Thus far, evolution of the science had 
taken place under the directing influence 
of some one leading thought or theory 
which served to mark the period which 
it dominated. 

52 



This, in a measure, is also true of the 
era which we are now about to consider. 
But the impulse experienced by chemis- 
try at this time, may, in its effects, be 
well compared to a progressive, ex- 
panding ripple, such as is caused by a 
disturbance in quiet waters. 

Quantitative relations were indeed the 
main issue, the central point, from which 
activity was diffused in all directions. 
But, so far reaching was this influence, 
that from now on it will be necessary to 
trace out, as well as may be, individual 
lines of thought which served to broaden 
the scope and reach of the science, while 
they themselves became merged in the 
general advance, the ever - widening 
spread of chemical knowledge. 

Analytical methods had by this time 
been sufficiently developed — in great part 
through the labors of Vauquelin and of 
Klaproth — so as to permit of quantitative 
determinations. 

While Bergman and Kirw^an were 
especially active in ascertaining the 
quantitative composition of certain neu- 
tral salts, Klaproth and Vauquelin chiefly 
studied mineral substances. The great 
question of the day then was, whether 
substances, in combining to form chem- 

53 



ical compounds, combined only in one, 
or, at most, in a few definite proportions 
by weight, or whether they could and 
would combine in any and all proportions. 
The latter view was upheld by Claude 
Louis BerthoUet. He conceded con- 
stancy in combination to only very few 
compounds, maintaining that most sub- 
stances could unite in any proportion to 
form compounds. For instance, he be- 
lieved that iron and oxygen could unite 
in any and every proportion and placed 
ferrous oxide and ferric oxide as the two 
limits. In his Essaide Statique Chiinique^ 
published in 1803, he attempted to ex- 
plain, in analogy with Newton's theory 
of gravitation, the chemical changes 
which bodies can experience. 

Lavoisier fully appreciated the fact that 
the combination of chemical elements 
takes place in definite proportions by 
weight. But it was Cavendish who first 
furnished proof of the existence of the 
law of combination in definite propor- 
tions. To him also belongs the credit of 
first introducing ''equivalency," the 
idea and the word, into chemistry. 

It was, however, the French chemist 
Joseph Louis Proust who gave a con- 
clusive demonstration of the fact, that 
54 



chemical combination of bodies does not 
take place in any and every proportion, 
but that such combination occurs only in 
one, or at most in a few simple ratios. 
Proust pointed out the sources of error 
into which many other analysts had 
fallen, and in so doing based all of his 
conclusions on exact analytical data. 
His views w^ere diametrically opposed to 
those of BerthoUet, but they soon came 
to be accepted as affording the correct 
explanation of facts ascertained by care- 
ful observation. 

The foundations of stoichiometry, the Atomic 
mathematics of chemistry, w^ere laid ^^^^ 
about this time, the closing quarter of 
the eighteenth century, by two German 
scientists, Carl Friedrich Wenzel and 
Jeremias Benjamin Richter. Their work 
was, however, overlooked by most of their 
contemporaries and only received the 
appreciation it so well deserved at a 
later date, w^hen general attention was 
given to the labors of John Dalton. 

The first conception of the atomic 
theory — the crowning glory of Dalton 's 
great achievements in science — was due 
to his perception of the fact, that w^hen- 
ever a definite amount by weight of one 
substance combines in varying proportion 
55 



with another substance, the proportions 
in which combination takes place bear a 
simple ratio to one another. 

The view that matter consists of 
minute and indivisible particles had been 
held for many centuries — even, as will be 
remembered, by the Greek philosophers 
of old. The idea that chemical com- 
binations were due to the coalescing of 
unlike particles had been advanced by 
Kirvan in 1783, and by Higgins in 1789. 

It can therefore not be claimed that 
the conception of the atomic theory 
originated with Dalton. However, it 
was he who first impressed upon this 
theory — a theory dealing with the 
constitution of matter — the quantitative 
aspect . 

He held that different weights charac- 
terize the atoms of the various elements \ 
that each element is composed of similar 
atoms of definite weight, and he expressed 
in his theory the law of multiple propor- 
tions : if two elements combine in dif- 
ferent proportions, the relative amounts 
of the one which combine with a fixed 
amount of the other are simple multiples 
of each other. As a sequence of his 
considerations it follows that the total 
atomic weight of a compound (the 
56 



molecular weight), is equivalent to the 
sum of the atomic weights of its con- 
stituents. 

The first reference to his atomic theory 
was made by Dalton in a paper read 
before an English philosophical society, 
October 23d, 1803, when he alluded to 
an inquiry he was making ' ' into the 
relative weights of the ultimate particles 
of bodies." The first published account 
of Dalton' s Atomic Theory is to be 
found in the work of one of his friends, 
Thomas Thomson, in the third edition of 
the Syste7n of Chemistry^ which appeared 
in 1807. A New System of Che77tical 
Philosophy ^ which issued from Dalton' s 
own pen in the following year, contains 
a full exposition of his ideas. These 
views of the quantitative relations 
governing chemical compounds, practi- 
cally form the basis of our chemistry of 
to-day. 

Introduction and futherance of Dal- 
ton's atomic theory was brought about 
chiefly by Thomson, by Wollaston, and 
by the great Swedish chemist, Berzelius. 
Jons Jacob Berzelius had been forcibly 
impressed with the writings of Richter, 
previously alluded to, and had entered 
upon an extensive investigation of cer- 
57 



tain salts in order to test the validity of 
Richter's views and claims. 

When Dalton's theory came to his 
knowledge, the analytical results which 
Berzelius had himself obtained bore wit- 
ness to the cotrectness of Dalton's^ 
reasoning. Painstaking experimental 
corroboration of Dalton's atomic theor>r 
must ever be counted as one of the most 
valuable contributions which Berzelius 
has made to chemistry. 
Law of The truth of Dalton's Atomic Theory 
w^as also borne out by the discovery, 
made in 1805, by Alexander von Hum- 
boldt and by Gay-Lussac, that two 
volumes of hydrogen combine with one 
volume of oxygen to form water. This 
ultimately led to the determination of 
the law which governs the volume com- 
bination of gases, the so-called Law of 
Volumes, announced by Gay-Lussac in 
1808. This law holds that the ratio in 
w^hich gases combine by volume is always 
a simple one, and that the volume of the 
resulting gaseous product bears a simple 
ratio to the volumes of its constituents. 
Dalton at first took issue with Gay- 
Lussac's statements and reasoning, for 
the latter made no distinction between 
atoms and atom-complexes, now termed 
58 



molecules. But in 1811 an Italian phy- Avoga- 
sicist, Amadeo Avogadro, succeeded in Hypo- 
showing, by establishing a difference be- thesis 
tween molecules integrantes and molecules 
eleme7ttaires, integral and elementary 
molecules, that the observations of Gay- 
Lussac and the teachings of Dalton were 
in full accord. Our term molecules cor- 
responds to the first of these conceptions, 
our term atoms to the second. Mole- 
cules are regarded as composed of indi- 
visible atoms. Avogadro was the first to 
demonstrate that equal volumes of all 
gases contain an equal number of mole- 
cules. 

Ampere's name is often linked with 
Avogadro' s theory, but the essay of 
the former did not appear until three 
years after Avogadro had made his 
announcement. Yet it was only in 1858, 
through Cannizzarro's able presentation 
of Avogadro' s work, that the latter re- 
ceived the recognition which it so justly 
deserved. 

An hypothesis was advanced in 1815 Prout's 
by an English physician, Dr. Prout, to J^gg^s' 
the effect that the atomic weights of all 
elements are whole numbers and that 
the elements themselves are condensa- 
tion-products of hydrogen. 
59 



While the claim that the atomic- 
weights are simple multiples of the 
atomic weight of hydrogen, has long aga 
been completely disproven by exact 
analytical determinations, yet it must not 
be overlooked that Front's claims gave 
the impetus to many most valuable in- 
vestigations which have been carried out 
with the utmost refinement of analytical 
skill. It is through such most accurate 
determinations of some of Nature's con- 
stants, that chemistry has justly gained 
the distinction of ranking as one of the 
exact sciences. 
Law of In 1 819, Dulong and Petit discovered 
and Pet^ the fact, that the specific heat of an 
element is inversely proportional to its 
atomic weight, or, as they expressed it, 
that the atoms of the different elements 
have the same capacity for heat. 

Specific heat is defined as the ratio of 
the amount of heat required to raise a 
given weight of a body one degree in 
temperature, compared to the amount of 
heat required to raise the same weight 
of water to the same extent. As the 
average value of the product of the 
specific heat of an element by its atomic 
weight is about 6.4, a simple division of 
this constant by the specific heat of the 
60 



•element in the solid state, gives approx- 
imately the weight of an atom of that 
element, thus affording valuable indica- 
tions in determining these very import- 
ant values, the atomic weights. 

Mitscherlich's theory of isomorphism, Isomor- 
that compounds of analogous composi- P ^^^ 
tion and containing the same number of 
atoms assume the same form in crystal- 
lizing, was, b}^ Berzelius, considered to 
be of value in the determination of atomic 
weights. Time, however, has proven that 
the results which this theory has yielded 
are deserving of less credit and credence 
than was once accorded them. 

Experiment having conclusively shown Chem- 
that in numerous instances substitu- Equita- 
tion of one element for another could be lents and 
effected, the relative amounts of the 
different elements which could thus re- 
place each other naturally called for 
consideration. The term equivalent was 
applied to the smallest amount b}^ weight 
of an element which could combine with 
or replace the unit weight of hydrogen. 
The weight of an atom, the atomic 
weight of an element, must then be iden- 
tical with or must be some multiple of 
this value. 

For a tune considerable confusion 

6r i 



reigned in this question of atomic 
weights and chemical equivalents, until, 
chiefly through the researches of Edward 
Frankland on the organo-metallic sub- 
stances, the idea of valence was intro- 
duced. 

The terms valence, valency, or quanti- 
valence designate the degree of combin- 
ing power of an atom of any element, 
compared with the combining power of 
an atom of hydrogen selected as unity. 
According to the degree of the combin- 
ing power thus defined, the elements are 
classed as monads, dyads, triads, etc. 
This means that one atom of an element 
can combine with or replace one, two, 
three or more atoms of hydrogen, as the 
case may be. 

The relation betw^een the chemical 
equivalent and the atomic weight of an 
element is expressed by the formula : the 
atomic weight of an element is equal to 
the product of its chemical equivalent by 
its valence. Thus, in the case of monads, 
atomic w^eight and chemical equivalent 
are identical; in dyads, the atomic weight 
is equal to twice, in triads it is equal to 
three times the chemical equivalent of 
the element. 

The importance of exact determina- 
62 



tion of the atomic weight values of the Atomic 
elements will be appreciated, when it is Weights 
remembered that these values may be 
regarded as the constellations by which 
the courses of chemistry are shaped. 

One of the most eminent chemists who 
ever engaged in the determination of 
atomic weights was Jean Servais Stas, a 
Belgian. He was a pupil of Dumas ; his 
results, based on experiments made with 
larger quantities of material than are 
usually employed in such determinations, 
furnished much of the evidence that dis- 
proved the hypothesis of Prout. 

Among American chemists who have 
achieved especial distinction in work 
along these lines, there should be men- 
tioned Morley, Clarke and Richards. 
Since 1893 ^^ American Committee on 
Atomic Weights has issued, — through the 
pen of F. W. Clarke, — annual reports on 
these values. 

The table of Atomic Weights given Table of 
on page 65 has been recommended for ^°?"\^^ 
general adoption in analytical practice 
by a commission consisting of H. 
Landolt, W. Ostwald and K. Seubert. 
This representative commission was 
appointed by the German Chemical 
Society. 

63 



Its members recommend that : 

1. The atomic weight of oxygen be 
taken as 16.000, and that the atomic 
weights of the other elements be calcu- 
lated on the basis of their combining 
ratios with oxygen, directly or indirectly 
determined. 

2. The following atomic weights of 
the elements be adopted in practice, as 
they are probably the most correct values 
known at the present time. (See table.) 

These numbers are, as a rule, given 
only with so many decimals that even 
the last one may be regarded as accurate. 
In consequence, the atomic weights de- 
termined by Stas, in which the errors 
amount to from 3 to 6 units in the third 
decimal, are given with two decimals ; 
the other atomic weights, which have 
been more accurately determined, are 
given with one decimal, and those less 
accurately determined are given without 
decimals. Exceptions to this rule have 
been made only in the cases of nickel, 
bismuth and tin, marked with an asterisk 
in the table. 

In the case of nickel this was done in 
order to emphasize the difference be- 
tween the atomic weights of cobalt and 
nickel, although in both values there 
64 



<^ 



1-1 ic 1-t on 



^- ^^ rH C^ Oi 1— t —'CVJ 1— t 












s lis .2 a 






£"51 






^s 










^^S^;z;z;z;co^;i,2,p:p.;2^ 






^ 




•X- 


E 




s 


-<* 


^ 




:2 




-^« 


^1 


^s 


m-- 


zrl^ 


s 


5^1 


Ti 


?^g 


05 


2 


|Sgg2^g 









;Ki:'J:^S:5 



may be possible deviations of ± 0.2. 
The true atomic weights of bismuth and 
tin are not correct to a certainty, to 
within 0.1. The value of hydrogen is 
1.008, correct to within o.ooi, but the 
approximation of i.oi has been regarded 
as permissible for the requirements of 
practice, as it involves an error of only 
one-fifth of one per cent. The values 
given for the elements marked in the 
table with interrogation points are not 
necessaril}^ exact within whole units of 
the atomic weights assigned. 

Chemistry has been exceptionally fa- 
vored in the last year or two by the 
discovery of new elements. 

A study of argon and helium, consti- 
tuents of our atmosphere, has led to the 
discovery of several other new element- 
ary substances. Thus, Ramsay and Tra- 
vers have recently isolated from liquefied 
argon three new bodies, krypton (hid- 
den), neon (new) and metargon. 

All of these are gases and occur in the 
earth's atmosphere in minute amounts; 
neon, for instance, only to the extent of 
about one part in forty thousand parts 
of air. There seems to be some doubt as 
to whether metargon is or is not an 
element ; it is said to have about the 
66 



same atomic weight as argon, but is pos- 
sessed of difiEerent properties. It is a 
solid at the temperature of liquid air. 
Quite recently another new gas has been 
added to those previously obtained from 
liquefied argon ; xenon is the name that 
lias been assigned to it. 

In July, 1898, Professor Nasini of 
Padua announced that he had, while 
studying the gases emanating from the 
Solfatara di Pozzuoli and the fumarole 
of Vesuvius, discovered a new gaseous 
element. Coronium is the name given 
to this substance, now first found upon 
our earth, but which, on the evidence 
of the spectroscope, has for some time 
been known to exist in the corona of the 
sun. 

At the meeting of the American Asso- 
ciation for the Advancement of Science, 
in 1898, Charles F. Brush announced 
the finding of a new gas, which he had 
extracted from glass at low pressures. 
This new body is said to occur in the air 
and to be easily absorbed by numerous 
substances, especially by glass. On ac- 
count of its peculiar properties — its high 
molecular velocity, 105 miles per second, 
and its very low density, o.oooi if hydro- 
gen be taken as i.o — Brush suggested 
67 



that this might possibly be the ether, the 
existence of which is assumed in physics. 
The name which he proposed for this 
supposedly new element is, etherion. 
However, the possibility of this substance 
being water-vapor has been recently 
suggested by Sir William Crookes and 
further developments must be awaited 
before the question at issue can be deter- 
mined. 

The investigator last named has iso- 
lated from yttria a body to which he has 
given the name monium, from the Greek 
word for "alone." Its atomic weight 
will probably be about ii8 and it is said 
to enter readily into chemical combina- 
tion with other elements. 
Electro- Within the past century and a half 
ical chemistry has witnessed the birth and 
Theory the growth of a number of theories and 
hypotheses, which, while they have all 
exercised some influence, one way or an- 
other, on the development of our vScience, 
can here claim but a passing reference. 
Of these the first to call for attention 
is the electro-chemical theory of Berze- 
lius. Fundamentally this was based 
upon observations made by Sir Humphry 
Davy ; it held that every atom was en- 
dowed with certain amounts of both 
68 



positive and negative electricity. These 
electrical charges were supposed to be 
accumulated .on different parts of the 
atoms, giving rise to negative and posi- 
tive poles. It was the preponderance of 
the one or the other kind of electricity 
which, it was believed, determined the 
electrical character of an atom. Atoms 
electrijSed in an opposite sense would be 
attracted to, atoms bearing charges of 
the same kind would be repelled from 
one another. On the combination of 
atoms bearing unlike charges, neutraliza- 
tion of the same would result. 

Berzelius suggested the existence of Dual- 
compound atoms ; this view of the struc- \p^^ 
ture of matter came to be known as the 
dualistic theory. It was closely allied to 
the electro-chemical theory and is best 
considered in connection with the latter, 
which was, for almost twenty years, the 
dominant theory of chemistry. 

Reference, however brief, must be Fara- 
made of the important results secured by l^^-/ 
Michael Faraday in establishing the 
quantitative relations which obtain when 
electrical power is made to do chemical 
work. Faraday conceived the idea of 
sending an electric current successively 
through a series of cells which contained 
69 



different solutions which would permit 
the passing of electric currents. Such 
solutions are termed electrolytes, and his 
observations determined that an electric 
current of a given strength will set free 
equivalent quantities of the constituents 
of different electrolytes. His law of con- 
stant electrolytic action was enunciated 
in 1833 ; its discoverer believed that it 
would prove a valuable aid in the deter- 
mination of atomic weights. 
Attacks Dumas and other French chemists, 

on the ^T^ile ensrasred in studying: the atomic 
Atomic . . 7 , ^ . , 

Theory weights of the elements, were led, 

through their determinations of the spe- 
cific gravity of vapors at high tempera- 
tures, to seriously doubt the validity of 
the law of volumes. 

It chanced that Dumas worked chiefly 
upon substances the molecules of which 
were complex, a fact, however, unknown 
to the experimenter. Finally, and in 
consequence of his results, Dumas ques- 
tioned the truth of the law of Avogadro. 
Other evidence also seemed to point to 
the untenability of Avogadro' s conclu- 
sions, and Leopold Gmelin, a pupil of 
Berzelius, a most eminent chemist and 
the author of several important works on 
chemistry, was led to abandon the atomic 
70 



theory completely. Gmelin held that, 
as a rule, the proportions in which sub- 
stances could combine were unlimited in 
number. He issued a table of equiva- 
lents, which might be styled a list of 
combining numbers. When a choice of 
equivalents seemed permissible, the low- 
est value was selected. His views on 
these matters met with general favor and 
were incorporated in many text-books, 
even as late as thirty years ago. 

The theory of radicals can primarily Theory 
be traced to the writings of I^avoisier ; Radicals 
after passing through various modifica- 
tions it attained to prominence about the 
year 1838, having received its greatest 
impetus from an investigation under- 
taken in 1832, by Justus von I^iebig and 
by Wohler, " On the Radical of Benzoic 
Acid," which showed the existence of 
an atomic group — benzoyl — in oil of bit- 
ter almonds and its derivatives. As this 
theory, as well as the dualistic theory, 
involved the conception of atoms, both 
contributed to restore to favor Dalton's 
views, which had once been held in great 
esteem. 

An attempt to apply the theory of ^Ethertn 
radicals to organic compounds resulted ^^^'^ 
in the so-called *' ^therin " theory, 
71 



which was advanced by Dumas and 
Boullay, defiant gas, for which Berze- 
lius suggested the name " setherin," was 
regarded as a constituent of the alcohols, 
the sugars and other substances, these 
bodies being in their composition com- 
pared to the compounds of ammonia. 

Substi- Berzelius' theory of dualism was dis- 
tution pQsed of primarily through a research on 
wax-candles by Dumas, an investigation 
•in which the principle of substitution of 
chlorine for hydrogen was discovered 
and proven. Dumas further explained 
by his theory the formation of chloro- 
form and of chloral, w^hich bodies Liebig 
had obtained by the action of chlorine 
on alcohol. 
Nucleus Auguste Laurent, finding that Dumas' 

Theory ^^^^ ^£ substitution did not afford a valid 
interpretation of all the data observed, 
suggested his nucleus theory ; this was 
an outgrowth of the theory of radicals, 
but, instead of claiming the existence of 
atomic groups of stable and unchange- 
able composition, Laurent's views held 
that such groups admitted of changes by 
the substitution of equivalents. 

Unitary Notwithstanding the efforts of Berze- 

Theory ^.^^ ^^ uphold his dualistic theory, to 
achieve which he evolved the hypothesis 
72 



of conjugate compounds, and notwith- 
standing the labors of Kolbe, which were 
directed to the same end, Laurent and 
his friend Carl Gerhardt carried the day 
with their unitary theor3\ This latter 
maintained that the nature of a molecule 
was determined by the nature, the num- 
ber and the arrangement of the atoms 
which formed it, and furthermore, that 
these atoms were capable of being ex- 
changed for — that is, were capable of 
being replaced by — other atoms. 

Laurent and Gerhardt introduced the Theory 
theory of types. They originally recog- ^^yp^^ 
nized three types : water, ammonia and 
h^'drochloric acid, and in their classifica- 
tion the}^ sought to refer all compound 
substances to one or the other of these 
as model forms. The continued disco- 
very of new bodies, however, soon made 
the creation and adoption of other addi- 
tional types a necessity, and the type- 
theory ere long grew to be unwieldy and 
cumbersome. 

The first half of the nineteenth century The 
witnessed various attempts to trace rela- Periodic 
lions between the atomic weights of 
elements and some of their properties. 
Possibly the first instance of this kind 
which received general attention was 

73 



the work done by Dobereiner, who, in 
1829, found that certain elements have 
atomic weights which are approximately 
the mean of the atomic weights of two 
other elements closely resembling them 
in their properties. Dobereiner also as- 
certained that groups of three could be 
formed of some elements whose atomic 
weights were almost the same and which 
exhibited close analogies in most of their 
properties. A systematic classification- 
of the elements, basing on the similarity 
of their properties, was an ardent wish 
of this investigator. But, of course, ere 
this could be accomplished, accurate de- 
terminations of the atomic weights of all 
elements were imperative. 

The periodic law, which holds that the 
properties of the elements are periodic 
functions of their atomic weights, was 
established chiefly through the labors of 
Newlands, Mendeleeff and Lothar Meyer. 

It seems that the first communication 
Newlands made on this subject was pub- 
lished early in 1863. In the following 
3"ear he issued a list of the elements in 
the order of their atomic weights ; the 
announcement of the periodic law by the 
two other investigators named was made 
in 1869. 

74 



It is, however, the distinctive merit of 
Mendeleeff to have pointed out that the 
value of any given property of an element 
is practically an average of the values of 
the same property of two other elements 
w^hich immediately adjoin it, when the 
elements are arranged in a table progres- 
sively, in the order of their atomic 
weights. 

Moreover, this distinguished Russian 
chemist, from a close study of his tables 
illustrative of the periodic law, predicted 
the existence and the properties of cer- 
tain elements not then known. The 
discovery of Gallium, of Scandium and 
of Germanium, n^de respectively in 1875, 
1879 and 1886, brilliantly fulfilled the 
prophecy of Mendeleeff. 

Neon, ''the new one," furnishes the 
most recent instance of an element sought 
for because the probability of its exist- 
ence seemed indicated by a gap in a 
periodic arrangement of the elements. 
It w^as discovered in and isolated from 
air by William Ramsay, the well-known. 
English chemist, whose name is also- 
linked with that of lyord Rayleigh in the. 
discovery of argon and of helium. 

An arrangement of the elements into 
groups and series, based on the principles. 

75 



indicated, and a close study of their rela- 
tions, have led, not only to a prediction 
of the existence of undiscovered elements, 
but have, in some cases, also proved of 
great value in the detection of erroneous 
atomic weights. 

The periodicity of many chemical and 
physical properties of the elements — for 
instance, of valence, of electro-chemical 
and magnetic powers, the toxic pro- 
perties of metals, and so forth — has re- 
ceived careful attention. Through studies 
of this kind it has become possible, in 
some instances, to predict the action of 
certain medical preparations, their com- 
position and molecular structure being 
known. 

A tracing out of such and similar rela- 
tions is certainly of great interest. Of 
recent years, experienced teachers of 
chemistry have found a presentation of 
the fundamental data of their science 
based on the periodic law, of great di- 
dactic value. While the periodic law, so 
called, cannot as yet give a logical ac- 
counting of all phenomena, it seems be- 
yond question that it is to-day one of the 
most important theories of chemistry. 

The valency of the element carbon had 
been studied and determined by Frank- 
76 



land. His conclusion that carbon is Stereo- 

Chem- 



tetra-valent was confirmed by the inde- 
pendent investigations of August Kekule, 
who, as a result of his researches into 
the manner of combination of carbon 
atoms mter se, laid the foundations of 
the important chain-theory, which has 
proved of great value in the realm of 
organic chemistry. 

Study of the structural arrangement 
of molecules, which resulted in the 
theory of the grouping of atoms in space, 
w^as initiated by the labors of Louis 
Pasteur, on the phenomena of isomerism 
exhibited by the tartaric acids. 

The work of Johnannes Wislicenus on 
lactic and sarcolactic acids, carried on in 
1873, foreshadowed the teachings of 
Van't Hoff and Le Bel, who, in 1874, 
almost at the same time but independ- 
ently of one another, formulated the 
principles of stereo-chemistry. 

Van't Hoff had elaborated his ideas 
with the object of explaining the property 
which many carbon-compounds, when in 
solution, possess of rotating the plane of 
polarized light. Le Bel, who followed 
Van't Hofl's announcement w4th his own 
conclusions on the subject but a few 
months later, was likewise led to his 

77 



istry 



conceptions by a study of the optical 
behavior of certain solutions. A treatise 
by F. W. Clarke, Chemistry of Three 
Dimensions, published in 1875, likewise 
emphasizes the conclusion that all mole- 
cules must be tri-dimensional. 

Thus far the compounds of carbon and 
the compounds of nitrogen have received 
most attention from those who have 
given special care to the developments of 
stereochemistry, but chemistry in general 
has undoubtedly been enriched in many 
ways through the stimulation given by 
this new departure from the old and well 
beaten tracks. 
The Development of the language of chem- 
rua^e^of is^^y ^^^ ^^ course been conditioned by 
Chem- and kept pace with the evolution of the 
*^ ^ science. The earliest terms employed in 
chemistry were, as a rule, suggestive of 
the origin of the substances which they 
denoted. The term sal, for instance, 
was applied since the earliest times to 
all substances having a salty taste. 
About the eighth century the attempt 
was made to distinguish between different 
substances having a salty taste, by add- 
ing a word descriptive of the origin of 
such substance ; thus, common salt was 
called sal maris, salt of the sea. 
78 



The thirteenth century witnessed the 
free use of certain symbols to denote 
some of the metals ; thus, gold, called 
Sol by the alchemists, was by them de- 
picted by a circle with a dot in its center; 
silver, in their language Ltma^ was re- 
presented by a crescent ; copper, which 
they termed Verucs, was denoted by a 
circle to the bottom of which a small 
cross was attached. 

The original and true meaning of 
these symbols is not known ; many and 
fanciful, however, have been the explana- 
tions suggested. For instance, it has been 
supposed that the symbol chosen for 
Venus represented a hand-mirror. 

Some of the alchemists saw in these 
symbols an indication of the chemical 
properties of the metals they denoted. 
Thus, the circle was held to illustrate 
perfection of the metallic condition, the 
semi-circle an approximation to this 
state ; however, an attempt to trace the 
various signs which were gradually intro- 
duced into the science and the numerous 
transmutations which they suffered in 
the course of time, would carry us far 
beyond the purpose and the limit of 
these pages. 

Reference by name only can here be 

79 



made to the systems of symbols used by 
Geoffrey, by Bergman, by Dalton, hy 
Berzelius, by Hassenfratz and Adet. 

The last named was specifically in- 
tended to accompany the chemical no- 
menclature devised by Lavoisier, De 
Morveau and colleagues, the system 
which is the foundation of the one em- 
ployed at the present time. 

Within the past decade various at- 
tempts have been made to agree upon 
some method of chemical nomenclature 
and notation which should meet with 
universal acceptance. Concerning the 
names and the symbols of the elements, 
those known to the ancients mostly retain 
their original appellation. In naming 
elements the discovery of which belongs 
to a later date, it has become customary in 
the case of metals to assign the termina- 
tion 7im or tu?n to the name selected ; in 
the case of non-metals, to make the end- 
ing of the appellation tne, o?i or g-e?z. The 
choice of the name of an element rests, 
of course, with its discoverer. In some 
cases the names of the planets have been 
used for the purpose ; thus. Mercury, 
Tellurium, Selenium own as their spon- 
sors respectively Mercury, the earth and 
the moon. 

80 



In other instances the patriotism of the 
discoverer has immortaUzed the name of 
his country by bestowing the same upon 
the newly found substance. Columbium, 
Germanium and Gallium may be cited in 
illustration. The names of deities have 
also been pressed into service to this end; 
thus, Thorium from Thor, one of the 
gods of Norse mythology. 

Sometimes the name which an element 
bears has been suggested by some dis- 
tinctive property which it possesses. 
Iridium is derived from the Latin word 
iris, 2l rainbow ; Iodine from the Greek 
term for the violet ; Barium from the 
same language, from the word which 
denotes weighty. 

The names of chemical substances, of 
elements and of compounds, are fre- 
quently indicated by symbols. As a rule 
the symbols which denote the elements 
are indicative of their names and usually 
consist of the initial, or of the initial and 
some other letter of such name. Thus, 
carbon is designated by the letter C, cal- 
cium by the letters Ca, and copper by 
the letters Cu, these last being taken 
from the Latin appellation of copper, 
cupy^um. 

It is an important matter to remember 
8i 



that the symbol of an element stands not 
only for its name, but represents at the 
same time a definite amount of the ele- 
ment — the weight of one atom. 

An atom is defined to be the smallest 
quantity of matter which can enter into 
chemical combination. If it be desired 
to indicate more than one atom, the 
requisite numeral is placed with the sym- 
bol. The symbols of compounds, usually 
termed formulae, are simply combinations 
of the symbols of the elements forming 
the compound and of numerals which 
indicate the number of atoms of the 
elements which are present in the com- 
pound ; thus, water is a compound of two 
gases, hydrogen and oxygen. The small- 
est amount of water, which can exist as 
such, contains two atoms of hydrogen 
and one atom of oxygen ; its formula- 
is therefore H^O. 

By a simple and ingenious system of 
terminals and of prefixes, taken in part 
from the lyatin and the Greek languages, 
chemists are enabled to have the name 
of a compound indicate to a certain ex- 
tent its chemical composition. 

The chemical composition of a com- 
pound can be concisely expressed in a 
formula ; from the chemical formula of a 
82 



substance, one versed in the language of 
chemistry can usually designate by name 
the substance represented. 

When elements or compounds aie sub- 
jected to influences which cause them to 
undergo changes, the reactions can be 
indicated by the aid of symbols and for- 
mulae. As matter is indestructible, 
nothing is lost in these reactions, and 
such expressions of change must there- 
fore, of necessit}', be equations ; they are 
termed chemical equations. Chemical 
equations are known respectively as syn- 
thetic, analytic, and metathetic, as they 
represent the formation of substances by 
the union, the decomposition, or the 
interchange of constituents. 

It was during the epoch of iatro-chem- Didactic 
istry that chemistry was first taught at jg^nT' 
the universities. At first the teaching 
of this subject was included in the 
lectures on medicine delivered by pro- 
fessors of that faculty. The first lecturer 
who treated chemistry as an independent 
subject was a German, Johann Hart- 
mann. He spoke at the high school at 
Marburg, in the first quarter of the 
seventeenth century. 

University instruction in laboratory 
practice was established much later, — in 

83 



fact, only towards the end of the centur3r 
last named ; the first public chemical 
laboratory for purposes of instruction 
was founded in 1683, b}^ the council of 
Nuremberg ; it was situate at Altorf , 
and its first director was Johann Moritz 
Hofmann. 

Lectures on chemistry, illustrated by 
experiments to serve didactic purposes, 
were introduced in France about one 
hundred 3'ears ago. In England, Sir 
Humphry Davy is credited with making 
this kind of instruction popular, and 
other CDuntries soon followed the novel 
practice. Modern methods of laboratory 
instruction in chemistry are generally 
believed to have been inaugurated by 
Justus von Liebig ; at least it is certain 
that his laboratory was one of the first to 
be established, and the same has certainly 
made its influence felt all over Germany 
and far beyond her borders. 
Manuals One of the earliest works on chemical 
^ ist?y 'Subjects which can in any way be looked 
upon as a text-book, is an English pub- 
lication, Compoicnd of Alchyjnie, which 
was prepared by George Ripley, about 
the year 1471. 

In an introduction in verse, with 
which he prefaces his volume, he, after 
84 



informing his readers of his intentions, 
outlines the table of contents : 

*' But into Chapters thys Treatis I shall devyde, 
In numbre twelve, with dew recapytulatyon ; 
Superfluous rehearsalls I lay asyde, 
Indendyng only to give trew informatyon 
Both of the theoryke and practycall operatyon: 
That by my wrytyng who so wyll guyded be, 
Of hys intente perfyctly speed shall he.'* 

Agricola's work, De fe me tallica, pub- 
lished in 1546, contains a good i^esiune of 
the art of metallurgy as it was under- 
stood at that time, but the first general 
treatise on chemistry is probably the 
Alchy77iia, by Andreas Libau, or Libavius, 
as he was often called. This work, 
published in 1595, is divided into two 
sections ; the first of these describes 
chemical operations and apparatus and 
contains directions for the regulation and 
the application of fire. The second part 
of the book treats of the preparation and 
the properties of chemical substances 
and compounds. No consideration is 
given in this book to theoretical dis- 
cussions. 

Quite a number of works on chemistry 

were issued in the seventeenth century ; 

some of these laid special stress on 

medical chemistry, others were more 

85 



general in their character. Of these, pos- 
sibly the Coiirs de Chymie, published by 
Nicolaus Ivcmery in 1675, and the Chymia 
Philosophica, by Jacob Earner, which was 
issued in 1689, were the most important. 

The standard work of Hermann Boer- 
have, Elementa Chemiae, first published 
in 1732, consists of two parts, the first 
of which deals with the theory, the 
second with the practice of chemistry. 
As representative works of the phlogistic 
and of the anti-phlogistic schools re- 
spectively, there might be mentioned 
Georg Ernst Stahl's Fiuidamenta Chemiae 
DogiJiaticae et Ratioiialis and Antoine 
Laurent lyavoisier's Elements de Chimie, 

The original of the Lehr^hcch der 
Cheviie, by Berzelius, the first volume of 
w^hich appeared in 1808, experienced 
many editions and also a translation into 
the German tongue. This work remained 
an authoritative work during the greater 
part of the first half of this century. 

Among the standard English manuals 
of chemistry which this century has pro- 
duced, probably none outranks the 
Treatise on Chemistry, by Roscoe and 
Schorlemmer. Of English works of 
reference in this science, the Dictionary 
of Chemistry, by Henry Watts, and the 
86 



revised edition of this publication by 
Morley and Muir, undoubtedly hold first 
place. 

However, it would be a great and 
profitless task to attempt here a recital 
of the wealth of chemical literature — a 
store-house of treasure — to which all 
civilized nations of the world have con- 
tributed. Some conception of its ex- 
tent may be gained by learning that 
A Select Bibliography of Che^nistry^ 1492- 

1892, prepared by the distinguished 
American bibliographer and chemist, 
H. Carrington Bolton, and published in 

1893, enumerates no less than twelve 
thousand and thirty-one titles of inde- 
pendent books and their translations. 

Of these, four thousand five hundred 
and seven titles are credited to the Ger- 
man, two thousand seven hundred and 
sixty-five to the English, and two thou- 
sand one hundred and forty-one to the 
French language. 

Two supplements of this most valuable 
w^ork add respectively about six thousand 
and eight thousand titles to the number 
above given. The latter of these volumes 
is limited entirely to the recording of 
dissertations, while a Caialogice of Scien- 
tific Periodicals, in which of course many 

87 



journals on chemistry are included, and 
which has also issued from the pen of 
Professor Bolton, lists no less than eight 
thousand six hundred titles. 
Chem- Appreciation of the wide domain legi- 
Analysis timately open to chemistry brought with 
it application of its teachings and prin- 
ciples in many ways to many problems. 
The directing influence in such adapta- 
tions was, of course, chemical analysis, 
which has for its object the resolving of 
substances into, and a determination of, 
their components. 

With a perfecting of the methods of 
chemical analysis, a more accurate 
knowledge and understanding of the 
composition, the properties and the be- 
havior' of the substances analyzed was 
gained. In consequence, new processes 
of manufacture could be devised, those 
in existence could be more carefully fol- 
lowed, controlled and improved, and 
thereby, in many instances, a lowering in 
the cost of production effected. 

Notwithstanding the great importance 
of analytical chemistry, the purely scien- 
tific aspect of this branch of the science 
had, up to the present decade, been sadly 
neglected, although in its practical as- 
pects and details analytical chemistry 
88 



iad received great attention and care for 
many years. It was Wilhelm Ostwald's 
work, The Scientific Foundations of Aria- 
lytical Chemistry, published in 1894, 
which marked a pioneering venture into 
this inviting but theretofore practically 
unexplored domain. 

In chemical anal3^sis distinction is 
made between proximate and ultimate 
analysis. Aim of the former is the de- 
termination of individual groups existing 
in a substance. Thus, milk consists of 
water, fats, albumenoids, sugar and salts; 
a proximate analysis of milk would in- 
volve the determination of these consti- 
tuents, as such. 

Ultimate analysis is concerned with 
the determination of the individual ele- 
ments which enter into the constitution 
of a substance. In the illustration cited, 
for instance, it would be the task of ulti- 
mate analysis to determine the carbon, 
the hydrogen, the oxygen and all other 
elementary components of the substances 
which have been enumerated as consti- 
tuents of milk. 

Methods of chemical analysis must of 
course be adapted to the physical char- 
acter of the bodies to which they are 
applied. Gases, liquids, solids, call for 
89 



different modes of treatment, which must 
be especially suited and adapted to their 
respective properties. It is a frequent 
practice of the anal3^st to bring a body 
from one state of aggregation into an- 
other, for instance, to transform a solid 
substance into a solution, before subject- 
ing it to an anah^tical examination. 

When the object of an analysis is only 
the ascertaining of the constituents of a 
substance, — that is to say, when no at- 
tempt is made to determine how much of 
each constituent is present, — the process 
is designated one of qualitative analysis. 

If, however, a knowledge of the 
amounts in which the constituents are 
present be desired, the analysis assumes 
the character of a quantitative determina- 
tion. In practicing the latter, distinction 
is made between gravimetric anal3'sis and 
volumetric anah^sis, according to the 
manner in which the quantitative deter- 
mination is effected. If the amounts of 
substances are ascertained by weighing, 
the work is termed gravimetric ; if by the 
use of measured volumes of reagents, the 
process is designated one of volumetric 
analysis. 

It has already been mentioned that the 
era of quantitative anah^sis was intro- 
90 



duced through the balance coming into 
general use in chemistry. The refinement 
and degree of accuracy to which many 
modem chemical determinations can lay 
claim is marked, and this is, in no small 
measure, due to the exercise of the 
mechanical ingenuity and skill which are 
nowadays bestowed upon the manufac- 
ture of analytical balances. 

For many centuries, and in fact up to 
U'ithin a few centuries, fire was consid- 
ered to be the principal agent for the 
bringing about of chemical changes. 
How firm a hold this belief had on the 
minds of workers in the science, may be 
inferred from a motto placed in a text- 
book on chemistry that was published in 
1663: 

Si7ie igni 7iihil operayiiur. 

Although fire played so prominent a 
role in the doings of the earlier investi- 
gators, yet the measurement of tempera- 
tures was but roughly approximate and 
very crude until Boerhave demonstrated 
the necessity and importance of employ- 
ing thermometers in many chemical in- 
vestigations. 

The construction of thermometers of 
the present type, containing a fluid, was 
first carried out about the middle of the 

91 



seventeenth, century, by members of the 
Academia del Cime?tto. Fahrenheit, in 
1 714, employed mercury for the filling of 
thermometers, and Boerhave, in his 
famous treatise on chemistry, expressed 
the boiling- and the melting-points of 
substances in degrees Fahrenheit. 

To secure the heat needed for their 
operations, the alchemists and their suc- 
cessors in the science paid great attention 
to the form and to the construction of 
their furnaces. Among the fuels used 
were wood, wood-charcoal, coal, peat, 
alcohol and oil. For the obtaining of 
their highest temperatures they employed 
burning glasses, turning to the sun for 
the required energy. Some important 
additions to chemical knowledge resulted 
from so practical a sun-cult ; combustion 
of the diamond is, for instance, said to 
have been first accomplished by the help 
of the sun's rays. 

The obtainment of high temperatures 
by the use of oxygen was introduced by 
Priestley, who caused a jet of this gas to 
impinge on a glowing coal. The first 
apparatus in which hydrogen was burned 
in oxygen, was constructed by Hare, in 
1 801. 

The two principal forms of dry analy- 
92 



sis which are practiced to-day are blow- 
pipe work, — which occupies itself with 
the behavior of substances under varying 
conditions of flame and generally in the 
presence of reagents, — and assaying, 
which is principalh' concerned with the 
determination of ores and metals by the 
processes of smelting and cupellation. 

The blowpipe, which was originally 
used for the soldering of metals, was first 
employed for the testing of minerals by 
Cronstedt and Engestroem. Bergman and 
one of his assistants, Johann Gottlieb 
Gahn, studied thoroughly the behavior 
of different substances and reagents un- 
der the flame of the blowpipe.- Their 
work on the testing of minerals by the 
blowpipe was published in 1779, and was 
the first treatise on this important branch 
of chemical analysis. Gahn's labors in 
this field continued for many years; after 
Berzelius had become his co-worker, the 
latter published a book on their methods 
and results, which experienced transla- 
tion into several languages. 

An Englishman, William Hyde Wol- 
laston, was another adept in the use of 
the blowpipe. He was a man of consid- 
erable ability and attainments, but per- 
haps his greatest achievement was the 
93 



working out of a method for the refining- 
of platinum, a method which could be 
applied on a manufacturing scale and 
which made possible the introduction of 
platinum vessels in the chemist's labora- 
tory. 

Assaying and blowpipe- work, or doci- 
macy, as it is often termed, are entirely 
distinct from the principles and methods 
of '' wet " analysis, a term often used to 
specify the working with solutions. 

This latter important branch of chem. 
istry received its first potent impulse 
through the labors of Bergman. His 
directions for the anal3'sis of mineral 
substances, which appeared in 1777 and 
the years following, were probably the 
first directions of the kind published. lu 
these he taught how minerals can be 
brought into a state of solution, by pow- 
dering them finely, by fusing them with 
the proper reagents and by then subject- 
ing them to the action of acids. 

While Bergman was thus probably the 
first to break ground in this new field, 
Martin Heinrich Klaproth was the one 
who fir«t brought chemical anatysis in- 
to systematic shape and who laid the 
foundations of that important structure, 
analytical chemistry, to the perfection of" 

94 



which so many able chemists have since 
given their best endeavors. 

One of the greatest benefits bestowed 
upon chemistry by Klaproth was the 
practice, which he was the first to intro- 
duce, of recording the results of his 
analyses exactly as he obtained them. 

As our mistakes should be stepping- 
stones to the truth, the value of Klap- 
roth' s procedure is patent. Thus, if the 
results of a complete analysis of a sub- 
stance should fall below loo per cent, to 
which they should figure, and if the dif- 
ference should prove too great to be 
accounted for on the plea of permissible 
experimental error, then search would 
naturally be instituted for the cause, 
duplicate analyses would be made, and 
the work, if faulty, corrected. If the 
duplicate analyses agreed, then there 
would be reason to suspect some con- 
stituent before not determined. Analysts 
prior to Klaproth did not pursue this 
course, and thereby they undoubtedly 
passed by many data which they could 
have secured. 

Klaproth left the imprint of his ability 
not only on analytical methods, but he 
likewise perfected much of the apparatus 
used in chemical manipulations ; the 

95 



introduction of silver crucibles, for in- 
stance, was due to him ; in fact, so great 
were his merits in these directions that 
he has been termed the ''creator" of 
analytical chemistr3^ 

In France the cause of analytical chem- 
istry was at that time furthered chiefly 
by Vauquelin, a pupil, and later on an 
assistant, of Fourcroy's. His researches 
extended to both mineral chemistry and 
to some of the so-called organic sub- 
stances. His lectures and his laboratory 
instruction were largely attended and 
exercised undoubted influence on the 
generation of chemists next succeeding. 
Of his writings, the Introduction to Chem- 
ical A?ialysis should be mentioned ; this 
was published in 1799, and a German 
translation of the same was made. Like 
several of his co-laborers in analytical 
chemistry, Vauquelin had the good for- 
tune to discover a new element, chro- 
mium. He also discovered and described 
the oxide of beryllium, the metal of 
which, beryllium, was isolated only thirty 
years later, by Wohler. 

The greatest improvements in analy- 
tical methods in those days were, how- 
ever, wrought by a Swedish chemist, 
Jons Jakob Berzelius, who had set for 
96 



himself as his goal the critical ex- 
amination of numerous chemical com- 
pounds in order to learn their exact 
composition and to discover the laws 
which governed their formation. His 
work pointed the way for the accurate 
determination of atomic weights and 
practically established the doctrine of 
proportions. 

Among the pupils of Berzelius, whose 
names are also deservedly eminent in the 
list of analytical chemists, there must be 
cited, Nils Nordenskjold, Heinrich and 
Gustav Rose, Mitscherlich, C. G. Gmelin 
and Friedrich Wohler. Heinrich Rose's 
Ausfuhrliches Ha7idbicch der Analytischen 
Ckemie long ranked as a model of its 
kind. 

Of English chemists who achieved 
marked success in this branch of chem- 
istry, there might be named Edward 
Howard, who gave much attention to 
the analysis of meteorites ; Smithson 
Tennant, who discovered osmium and. 
iridium, and who, in 1796, was the first 
to make an experimental investigation of 
the chemical nature of the diamond, 
showing the same to be but a pure form 
of carbon ; Dr. Henry, who devoted 
much skill to the analysis of gases, and 
97 



William Hyde Wollaston, whose worki 
has been previously referred to. 

One of the most distinguished analy- 
tical chemists of our own time was 
Carl Remigius Fresenius. An assistant 
of Justus von lyiebig's, in Giessen, and. 
later an assistant professor at that Uni- 
versity, he established at Wiesbaden, in - 
1848, a laboratory which has since gained 
a world-wide reputation. 

His manuals on Qualitative and Quan- 
titative Analysis are to-day regarded as 
the standard works on these subjects, 
and his Zeitschrift fur Ayialytische Chemie, 
founded in 1862, is still the leading 
journal of its kind. 
Organic Before* the time of Robert Boyle, all 
and^Svn- substances were classified in accordance 
thesis with their physical properties. Chloride 
of zinc, chloride of antimony and chloride 
of arsenic were designated respectively 
as butyrum zinci, antimonii, arsenid, 
simply because they all had about the 
consistency of butter ; they were actually 
classed with this substance. Oil of 
vitriol, the sulphuric acid of to-day, was 
placed into the same group with the 
fatty oils, while sugar was counted in 
with the salts because it was a colorless ^ 
substance soluble in water. 
98 



In a text-book on chemistry, entitled 
Cours de Chymie^ first published in 1675, 
the author, Nicolas lycmery, classified 
substances according to their source or 
origin ; he thus distinguished three 
classes of bodies, — mineral, vegetable and 
animal. Lemery's book was at the time 
regarded as the standard work on chem- 
istry, and as it experienced translation 
into many tongues, his system of classifi- 
cation met with general acceptance. 

It was only towards the close of the 
last century that the products of the 
vegetable and animal kingdoms, so called,, 
received any appreciable attention from: 
chemists. Scheele and Bergman studied, 
some of the organic acids and worked out 
methods for their analysis, while the 
subject of animal chemistry received con- 
sideration at the hands of Rouelle. 

Lavoisier determined the constituents 
of vegetable compounds to be, usually,, 
oxygen, hydrogen and carbon ; animal 
substances, he found, contained in addi- 
tion nitrogen, and sometimes phosphorus.. 
In Lavoisier's eyes, oxygen was, so to- 
speak, the centre of the chemical world ;. 
in most instances he sought to determine 
whether a body was in combination with 
oxygen, or, if not, whether its combina- 
99 



tion with oxygen could be effected. To 
a body thus in combination or capable of 
combining with oxygen he applied the 
term '^radical"; a radical might be 
either a simple or a compound substance. 
This was, as previously stated, the 
foundation of the theory of compound, 
radicals later advanced by Berzelius. 

Sharp distinction between animal and 
vegetable chemistry was gradually al- 
lowed to fall into disuse when it was 
ascertained that there were some sub- 
stances which occurred in both the ani- 
mal and the vegetable world ; then the 
products of both of these kingdoms were 
grouped together as organic substances, 
and were classed apart from bodies of a 
mineral, or, as it was termed, an inorganic 
origin. 

Berzelius, after a most thorough re- 
search, reached the conclusion that the 
so-called organic bodies were in their 
composition also subject to the laws of 
constant and multiple proportions. 

The boundary line between organic 
and inorganic substances was, however, 
not clearly defined. Gmelin cited, as a 
distinguishing characteristic, that organic 
bodies could not be formed artificially 
from their components, while synthesis, 



which means a building up from their 
constituents, was possible in the case of 
inorganic compounds. But other views 
were also held, the chemists of that time 
being by no means agreed as to what 
constituted a proper definition of organic 
and of inorganic substances. 

The discovery by Friedrich Wohler, 
in 1828, that amonium cyanate, a mineral 
substance, could be transformed into 
urea, distinctively an animal product, 
marks the first drawing aside of the veil 
wherewith Dame Nature was believed to 
screen the mysteries of the living world. 

At that time, the belief was commonly 
held that all compounds found in the 
animal and in the vegetable kingdom 
owed their existence to the influence of 
a mysterious vital force. The elements 
under the domain of life were supposed 
to be governed by laws of their own, 
and, while it was known that substances 
found in plants and animals could be 
caused to undergo changes and transfor- 
mations, it was not believed to be pos- 
sible that they could be artificially made 
from their component elements. 

It was a long time ere the full and 
and general bearing of Wohler' s discov- 
ery came to be thoroughly appreciated, 

lOI 



ere the belief in a vital force was aban- 
doned to be replaced by a well-founded 
faith in the possibility of the synthesis of 
all organic compounds. 
Spec- When, in analytical determinations, 
Analvsi^ the means and methods of chemistry 
alone are not sufficient to secure the 
required degree of accuracy in the results 
sought for, the aid of a sister-science, 
generally of physics, is invoked. 

An illustration in point is spectrum 
analysis, a field of investigation opened 
up through the use of an instrument 
called a spectroscope. By the aid of this 
device the chemist is enabled to learn 
the composition of many substances under 
the sun, in fact, even of the sun, by ex- 
amining the light which comes to us 
from that bod3\ 

When a beam of sunlight is allowed to 
pass through a prism, the various rays 
of which the white light consists are 
unequally refracted, and, in consequence, 
are separated from one another in emerg- 
ing from the prism. These vari-colored 
rays, exhibiting all the colors of the 
rainbow, are designated as the spectrum. 

Three kinds of spectra are distin- 
guished. The solar spectrum and the 
spectra given out by the stars consist of 



colored bands traversed in certain parts 
by dark lines. Solids heated to incan- 
descence, but emitting no vapors — plati- 
num, for instance — give rise to continuous 
spectra, that is, to bands of color un- 
broken by dark lines. Vapors of vola- 
tile substances, especially vapors of the 
metals, cause so-called bright line spectra. 
As each metal has a spectrum peculiar ta 
itself and which is perfectly characteris- 
tic with respect to the color, the position 
and the number of the. lines it exhibits, 
the value of spectrum analysis for the 
purposes of chemical research will be 
readily appreciated. 

Credit for applying the principles of 
spectrum analysis to problems of chem- 
istry belongs to two German chemists, 
Bunsen and Kirchhoff. By its aid they 
discovered the elements caesium and 
rubidium ; gallium, thallium and indium 
were likewise discovered by means of the 
spectroscope, by other analysts. 

In an address, entitled ' ' The Chem-^ 
istry of the Stars," recently delivered by 
J. Norman Lockyer, this distinguished 
scientist, after recounting recent infor- 
mation gained in stellar chemistry by 
means of the spectroscope, referred to 
the process of celestial evolution, and 
103 



suggested the probability that all cos- 
mical bodies were evolved from meteor- 
ites. Surely a great and important 
generalization to found on evidence sup- 
plied by a method of nature-study which 
had its modest beginning onl}- at the 
beginning of this centur3\ 
Electro- One of the most important advances 
istry i^ade in chemistry in the first decade of 
the nineteenth century, was the securing" 
of two new elements, potassium and 
sodium, from their compounds, potash 
and soda respectively, by the aid of 
electrical power. This was accomplished 
in 1807 by Sir Humphry Davy, who used 
electric currents in these investigations. 

Water had been decomposed electro- 
lytically, seven years earlier, by Nichol- 
son and Carlisle. Berzelius had tried 
the action of electricity on salt solutions, 
ammonia and other compounds, and Sir 
Humphry Davy commenced his work in 
this direction by a very careful study of 
the electrolytic decomposition of water. 

Davy's observations laid the founda- 
tion of the electro-chemical theory, 
w^hich, later on, was materially enlarged 
and elaborated by Berzelius. A number 
of new elements were discovered by dis- 
sociating chemical compounds by the aid 
104 



of the electric current. Besides potas- 
sium and sodium, calcium, barium, 
strontium, chlorine and iodine were thus 
added to the list of chemical elements. 
Among the French, these researches 
excited great interest, and Gay-IyUssac 
and Thenard paid great attention to the 
preparation of the alkalies named, potas- 
sium and sodium, by electro-chemical 
methods, in addition to seeking to obtain 
these metals by other processes of manu- 
facture. 

Employment of the electric current for 
the separation of metals was advocated 
in 1865 by Liickow, and its introduction 
into analytical chemistry was due chiefly 
to this investigator and to Gibbs. 
Within the past decade, thanks to the 
efforts of Wilhelm Ostwald, Alexander 
Classen, Robert Liipke, Edgar F. Smith 
and others, the methods of electro-chem- 
istry have reached so advanced a stage, 
that regular systems of qualitative 
analysis by electric currents have been 
devised, and by these means and 
methods satisfactory determinations of 
many bodies can now be made. 

A study of the influence of electricity 
on certain of the so-called organic vSub- 
stances is one of the latest phases upon 

105 



which electro-chemical investigation has 
entered. 
Physical Fraught with potent powers for the 
ist?y ^^^^' f^^ ^-^^ advancement of all chemical 
knowledge, are the teachings of physical 
chemistry. 

Physical chemistry is the name by 
which there is designated that border-land 
of science lying between chemistry and 
physics. Its scope may perhaps best be 
defined by stating that it aims at the 
solving of chemical problems by physical 
means and also at the solving of problems 
in physics b}^ invoking the aid of chem- 
ical methods. 

A pioneer in this field was Olivet 
Wolcott Gibbs, a distinguished Americai^ 
chemist. In German}-, Wilhelm Ostwald, 
AV. Xernst and J. H. Van't HofI are 
among the leaders of the movement along 
these lines. 

Other chemists whose names are iden- 
tified with advanced work in pure chem- 
istry are : Ira Remsen, J. P. Cooke, 
William Crookes, Arrhenius, Raoult, 
Wurtz, Le Bel, Guldberg and Waage. 
In Germany, the Zeitschrift fi'ir Physi- 
kalische Cheiiiie^ edited by Ostwald and 
Nernst ; in America, The Journal of 
Physical Chemistry, edited by Bancroft 
io6 



and Trevor, are the representative organs 
of this especial branch of the science. 

We may here not transgress into this 
fascinating domain nor enter into a dis- 
cussion of its interesting possibilities. 
Exploration of it has, so to say, hardly 
commenced, but even so, it has already 
yielded great treasures to science and is 
full of promise for the future. 

The origin of metallurgical knowledge Metal- 
dates back to prehistoric times, different qu^^ . 
nations ascribing the creation of the art istry 
to their gods and heroes. 

Gold and silver were probably the ear- 
liest known of the metals ; this is easily 
accounted for through their occurring in 
the native state, that is to vSay, in the 
elemental condition, so that they could 
be employed as found, without first hav- 
ing to be obtained from their ores. The 
oldest manufactured object of gold to 
w^hich a date can be assigned is a bead, 
shaped somewhat like a crescent, which 
was found by Monsieur de Morgan in a 
royal tomb at Nagada, in Egypt ; the 
probable date of erection of that struc- 
ture is about 4400 B.C. 

Nearly all ancient articles of gold 
which have been analyzed have been 
found to contain some silver. This 
107 



natural alloy of gold and silver— for 
such it may be considered — was termed 
electrum ; it occurred in considerable 
quantity in Asia Minor. The earliest 
coins, the introduction of which Herod- 
otus ascribes to the Iv3^dians, were made 
of electrum. They resembled oval bul- 
lets in shape and were stamped on one 
side only. Their use dates back about 
seven centuries before the beginning of 
our chronology. 

Pure silver in ancient times seems to 
have been used principally for the mak- 
ing of jewelry and of other ornaments. 
Reference to a ring of silver is to be 
found in a translation of The Book of the 
Dead by Wallis Budge ; this reference 
would seem to make the existence of 
silver rings date back to at least 3600 B.C. 

Copper and its alloy, bronze, have been 
known from the very earliest of times ; 
articles made therefrom have, it is 
claimed, been found in deposits dating 
back to the age of stone. In the tomb 
at Nagada, previously referred to, there 
was also found a button, which, accord- 
ing to the analysis of Berthelot, consisted 
almost wholly of pure copper. 

Copper articles of somewhat later dates 
are frequently found to contain arsenic ; 
108 



this was probably added to harden the 
copper. Tin alloyed with copper consti- 
tutes bronze ; objects made of this mate- 
rial were used in Egypt evidently in very 
early times. 

The use of iron was known to the 
Egyptians long before this metal passed 
into the hands of the Greeks and Ro- 
mans. The time when it was first used 
in Egypt is a matter of dispute. Lepsius 
holds that it was there employed fully 
five thousand years ago. 

Strange as it may seem, in spite of its 
wide usefulness this metal was regarded 
by the Egyptians as '* the impure metal/' 
and its handling was held to be a sin. 
This ancient superstition passed, together 
wnth the metal, into the keeping of other 
nations and may to this day be traced in 
various countries far distant from each 
other ; it is, for instance, encountered in 
Africa, in China and in Scotland. 

Several metallurgical operations were 
known to the Romans and the Greeks, 
but hardly any information has come 
down to us concerning the chemical pro- 
cesses employed in those times. Diodo- 
rus, in the second century before our era, 
described a process of cupelling gold for 
removing impurities from that metal. 
109 



The process of heating cinnabar with 
iron, in order to obtain metalUc mercury 
from this compound of mercury and sul- 
phur, was also then known. 

Mining was actively pursued in various 
countries, notabl}^ in Spain, France and 
Germany, as early as the eleventh cen- 
tury ; the mercury deposits in Idria w^ere 
discovered towards the end of the fif- 
teenth century, and the tin mines of 
England have been worked since very 
early times. 

During the age of medical chemistry 
Agricola carefully described the chemical 
operations involved in metallurgical pro- 
cesses. By-products were noticed and 
secured, and about the middle of the six- 
teenth centur}^ the discovery was made, 
in Germany, that cobalt oxide imparts a 
hlue color to glass. 

The eighteenth centur}^ brought Berg- 
man's investigation on the differences 
between cast - iron, wrought - iron and 
-Steel ; Reaumur's teaching of a practical 
process for the making of steel from 
iron, and Duhamel's study of the making 
of brass. About that time several trea- 
tises on metallurgy were published, 
among them Schlueter's extensive work, 
w^hich appeared in 1738. 



In the nineteenth century the process 
of making steel, devised by Sir Henry 
Bessemer, in 1856, has been perhaps the 
most important and, in its effects, the 
most far-reaching of all of the numerous 
advances made in metallurgical opera- 
tions. The removal of phosphorus from 
iron, by the Thomas-Gilchrist process, 
and the utilization of the resulting slag 
as a valuable fertilizer, mark other 
achievements of this century in this par- 
ticular field, which are of great import- 
ance and value. 

Considerable attention has also been 
given within recent decades to the mak- 
ing of various combinations of metals, 
alloys, as they are termed. New varieties 
of brass and of bronze have been manu- 
factured ; aluminium, which owes its 
present prominent position in the world 
of metals in a great measure to its cheap 
production by electro-chemical processes, 
forms the basis of a number of exceed- 
ingly valuable alloys, bronzes and others. 

Various methods have also been found 
for securing the intimate combination of 
iron and steel with varying amounts of 
carbon, nickel and other elements. This 
results in the securing of great strength 
and power of resistance for the finished 
III 



products. In this respect, indeed, tlie 
great and enduring struggle for supre- 
macy going on, the civilized world over, 
between heavy armorplate for purposes 
of defense and heavy projectiles for pur- 
poses of attack, may well be looked upon 
as an episode in the evolution of this 
particular branch of metallurgical chem- 
istry. 

Quite recently the United States Navy 
Department has received an extensive 
report concerning a very important ex- 
periment which extended over a period 
of four years, and which was made to 
determine the feasibility of attaching a 
covering of copper directly to the steel 
or iron hulls of vessels. 

The process employed is practically 
one of electro-plating, the copper being, 
as it were, fused directly into the plates 
of iron or steel. The coating of copper 
thus applied has a thickness of about 
one thirty-second of an inch. 

The results obtained in this Govern- 
ment trial have proved eminently satis- 
factory in every respect. The process is 
less costly than the process of copper- 
sheathing as ordinarily employed ; the 
hull of the vessel experimented upon was 
found to be free from all barnacles, even 

IT2 



after long continued service in southern 
waters, and last, but not least, it was 
established that no galvanic action had 
been set up between the iron and the 
copper, although such an occurence might 
have been feared. 

Taken all in all, the successful out- 
come of this crucial test seems to mark a 
new departure along lines where the need 
of improvement had long been felt and 
sought, and this new process will pro- 
bably prove to be of the greatest value to 
the shipping interests of the world. 

Incidental reference should here be 
made to the various metallic pigments 
which play quite a role in the arts and 
industries. Among such colors, we 
have white lead, paris green, zinc white 
and iron ochre. Salts of iron, chromium, 
aluminium, tin and potassium are also 
largely used in the dyeing and the print- 
ing of textile fabrics. 

The marvelous advances made by elec- 
tricity have caused its influence to be 
strongly felt also in matters chemical. 
The winning of metals by electrical pro- 
cesses has previously been mentioned, 
and the practical applications of electro- 
metallurgy in the arts and in manufacture 
are numerous. 

"3 



Electro-plating, the process of covering' 
surfaces with metallic deposits thrown 
down from solutions of their salts by 
electrical currents, has made wonderful 
strides since the first inception of the 
idea by de la Rive, in 1836. 

The production of whole series of 
chemical compounds, for instance, the 
silicides and the carbides, is also effected 
through the aid of powerful electric 
currents, which are caused to generate 
intense heat. Thus, carborundum, which 
is a carbide of silicon, is formed in 
the manner indicated, from a mixture 
of coal, sand and salt ; it has found con- 
siderable application in the arts, on 
account of its very great hardness, it 
replaces emery for many purposes and it 
is also used in the making of steel. 

Calcium carbide, which is made by 
fusing coke and lime in an electric fur- 
nace, 3'ields, when brought into contact 
with water, that brilliant illuminant, 
acetylene, which of late has entered into 
active competition with the illuminating 
gas now in common use. 
Mineral- The analytical work of Bergman, 
Ch^^^- ^^^^<^^^^^^ ^^^d Klaproth forms the true 
istry foundation of mineralogical chemistry, 
although sundry scattered observations 
114 



on the nature of minerals were made 
even in the seventeenth century. 

It was Hauy who called attention to 
the importance of the crystalline struc- 
ture of minerals, and in his system of 
classification he paid due regard no less 
to their physical than to their chemical 
properties. 

In 1824, Berzelius announced his clas- 
sification of minerals. This was based 
principally upon his own numerous 
analyses and soon displaced all other 
systems. 

At one time considerable importance 
was attached to the theory of isomor- 
phism, advanced by Eilhard Mitscherlich. 
This theory held that identity of crys- 
talline form was dependent only upon 
the number and the arrangement of the 
atoms in a molecule and was in no wise 
influenced by the chemical nature of 
these atoms. According to Mitscher- 
lich' s teachings, an equal number of 
atoms united in the same manner would 
always give rise to one and the same 
crystalline form. 

Among those who have been or are 
active workers in mineralogical chem- 
istry, there should be cited the names of 
James D. Dana, whose Text-book of 
115 



Mineralogy is a standard work, and C. 
Rammelsberg, of Berlin, the author of 
the Handbiich der Mineralchemie , who in 
his day also contributed largely to the 
advancement of this branch of chemistry. 
The first half of this century witnessed 
a few isolated attempts at the artificial 
formation of minerals, for instance, 
Gustav Rose's work on calc-spar and 
arragonite. But synthetic mineralogy, 
the producing of minerals in the labora- 
tory while seeking to imitate Nature's 
conditions, dates virtually from the 3^ear 
1 85 1, when systematic attempts in this 
direction were first planned and made. 

J The methods employed embraced work 

w^ith solutions as well as with fusions 
carried out at high temperatures ; the 
results have proven of great value to 
geology, by making possible the testing 
of many geological h3^potheses and by 
leading to the advancing of new theories. 
Geo- Among the most eminent German 

^gical ^^orkers in chemical geology were Bun- 

istry sen, who carefully studied the geysers of 

Iceland, and G. Bischof, who published 

a valuable treatise on the subject, the 

Lehrbuch der Chemischeii Geologie. 

Of American geologists who have 
attained to eminence in this field of 
116 



work, there should be named Thomas 
Sterry Hunt, who was long active in the 
geological surv^ey of Canada and whose 
work on questions of chemical mineral- 
ogy is highly esteemed, and James 
Furman Kemp, whose standard pub- 
lications on geology also contain various 
important contributions on topics of this 
character. 

The French have been most active in 
the synthetic work along these lines — to 
mention only St. Claire Deville, Troost, 
Sarasin and Moissan. Moissan, in 1892, 
succeeded in making minute diamonds 
by exposing sugar-carbon and iron 
filings, while under great pressure, to a 
temperature of over five thousand de- 
grees and then suddenly cooling the 
mass. 

A sudden chilling, under enormous 
pressure, seems to be a necessary con- 
dition for the synthesis of diamonds ; 
geologists have not yet succeeded in 
determining the mother- rock of this gem. 
An h3'pothesis recently advanced would 
assign to all diamonds an extra-terrestrial 
origin, holding that they are brought to 
this world by meteorites. Three sep- 
arate finds of diamonds in meteorites 
have been made. One of these mes- 
117 



sengers from space fell in Chile, another^ 
in Siberia and the third in Arizona, 
f U. S. America. 

■ While there is not, as 3^et, sufi&cient 

evidence at hand to establish the above 
mentioned hypothesis on anything like a 
probable basis, yet it remains an inter- 
esting fact that Moissan succeeded in 
obtaining diamonds synthetically, under 
conditions analogous to those to which 
meteorites that reach this earth are 
supposed to be subjected at one period 
of their existence. 
Phyto- The beginnings of phyto-chemistry, 
istry ^^^ chemistry of plant-life, can be traced 
back to investigations made at the close 
of the eighteenth century. 

Priestley, Senebier and others were 
familiar with the fact that green plants 
under the influence of sunlight v/ill re- 
move carbonic acid gas from the atmos- 
phere and decompose it. They were also 
aware of the fact that ammonia salts are 
of value in stimulating the growth of 
plants. 

Although the problems of plant-life, 
the mode and manner of plant-nourish- 
ment and growth, had engaged the 
labors of many trained observers for 
many years, yet, even during the first 
ii8 



three decades of this century the belief 
was almost universal that plants, like 
animals, derived their nourishment di- 
rectly from organic matter. 

It was Justus von Liebig who demon- 
strated the falsity of these views and who 
entirely disproved the humus-doctrine, 
as the theory held at that time was 
called. It was in 1840, after exhaustive 
investigations on the weathering of rocks, 
on the formation of soils and on the 
effects of rain and the gases which rain 
holds in solution, that von lyiebig pub- 
lished his classic work on the application 
of chemistry to agriculture and physi- 
ology. 

In this he demonstrated that the food 
of plants is inorganic in its nature. The 
parts played by carbonic acid, by water, 
by ammonia and by various mineral salts 
were pointed out, and the fact was estab- 
lished that restitution must be made to 
the soil of such constituents as are re- 
moved therefrom by vegetable growth, if 
a given soil is to continue producing 
crops indefinitely. 

When Nature is left to her own time 

and devices, she replenishes the needed 

store by the disintegration of the rocks. 

This is accomplished through the agency 

"9 



of frost, by the solvent power of water 
containing carbonic acid, and, last but 
not least, through the silent but ever- 
active agency of the industrious earth- 
worms. 

Our knowledge of the last named we 
owe chiefly to the illustrious naturalist, 
Charles Darwin. Earth-worms live in 
burrows, in the superficial layers of the 
ground. They can live anywhere in a 
layer of earth, provided only that the 
same retains a sufficient store of moisture, 
for dry air is fatal to them. The}^ live 
principally in the mold, less than one 
foot below the surface, but in dry weather 
they sometimes go down to a depth of 
eight feet. 

Their burrows end in small chambers, 
large enough to admit of the worms turn- 
ing in them. These burrows are formed 
through the earth being swallowed by the 
worms for the sake of the decomposing 
vegetable matter which it contains and 
on which the worms feed ; leaves also 
form part of the diet of these little 
animals. When decaying, these leaves 
give rise to the formation of certain, 
acids, but these acids are neutralized by 
some carbonate of calcium secreted by 
certain small glands the worms possess ; 



these glands empty into the alimentary 
canal. Digestion of the vegetable matter 
is secured by the aid of a digestive fluid 
which resembles the pancreatic juice of 
the higher animals ; it acts only when 
alkaline. 

One part of the alimentary canal of 
these worms forms a hard, muscular 
organ, which is capable of grinding the 
food into fine particles. Small stones, 
swallowed with the earth, act as mill- 
stones, and the earth therefore is con- 
tinually, as it were, passing through a 
mill, and is thus being constantly ground 
into a fine mold. 

After the earth has been thus treated 
by the earth-worms it is voided as cast- 
ings. The mold in a field passes through 
the bodies of these worms several times 
a day, and the earth particles are there- 
fore brought to the surface again and 
again to be acted on by the rain and 
carbonic acid. Furthermore, through, 
the collapsing of old burrows the mold! 
is kept constantly in slow movement, and 
its particles are thus continually ground 
against one another. It has been cal- 
culated that in one acre of land, suited 
to their needs, more than fifty thousand 
earth-worms can exist ; the importance 

121 



of their influence may therefore be readily 
inferred. 

However, when the conditions are suck 
that land cannot be allowed to lie fallow 
for the length of time needed by nature 
to carry out her purpose, chemistry comes 
to the rescue, and, accomplishing in a 
few hours the task that without her aid- 
would have required years, gives to the 
cultivator of the soil fertilizers, the 
needed food for his crops, in a form 
to be readily assimilated by the plants. 

Chemistry has taught man to know 
aright the requirements of Mother Earth, 
the conditions w^hich must be fulfilled to 
ensure bountiful crops. No longer need 
virgins be sacrificed to the Genius of 
Maize, as was done by some tribes of 
American Indians, in order to plead for 
a generous yield of the life-sustaining 
cereal. 

Notwithstanding the fact that the 
questions how plants feed and how plants- 
grow have claimed the interest and the- 
earnest work of many distinguished in- 
vestigators these many years, we have 
as yet no positive knowledge as to the 
exact manner in which the inorganic 
constituents, water and carbonic acid 
gas, are by the plants transformed into^ 



organic products, such as starch, the 
sugars and cellulose. These substances, 
produced by the plants are the food of 
animals ; these in turn, when they die, 
again furnish the chemical compounds 
necessary for the life and the growth of 
plants, thus establishing and completing^ 
an endless cycle. 

Another tempting problem which has 
received much attention at the hands of 
phyto-chemists, but which has as yet not 
found its full solution, is the chemistr^^ 
of the color changes which foliage ex- 
periences in the fall. 

It is, of course, well known that plants, 
their leaves and their flow^ers owe their 
colors primarily to the magic touch of 
light. Thus, a leaf in its period of 
vitality absorbs all tints of light except 
the green ; this it reflects, and hence the 
leaf shows a green color. But as the 
vitality of the leaf declines, changes — 
chemical changes — occur in at least one. 
of its constituents, the chlorophyll, and 
then the sunlight falling upon the leaf is 
differently affected. Various hues are 
reflected as the chemical changes pro- 
gress. The leaf, erstwhile green, assumes 
in turn tints of yellow, orange, red — a 
play of colors which serves to render our 
123 



woodlands so beautiful in autumn. It 
has been stated that the sequence in 
which the colors of the turning leaves 
appear is the same as the order in which 
the colors of the spectrum range ; fol- 
lowing the green come yellow, orange 
and red — evidently favorite tints on 
the palette of Nature. 
Techno- The achievements of chemistry in the 
Chem- ^^^^ ^^^ industries are so vast and so 
istry varied, that the mere attempt to enumer- 
ate them all would prove a task scarcely 
less formidable than the counting of 
the denizens of starland, some twenty 
thousand of which are believed to exist 
for every one that is visible to the un- 
aided eye. 

Pure chemistry and applied chemistry 
are ever inter-active. The latter profits 
by the advances made by the former, 
while pure chemistry is in turn benefited 
by the new possibilities and opportuni- 
ties created and offered by the industries. 
While the evolution of the science and 
its ministrations have gone hand in hand, 
yet it is unquestioned that a practical, 
an empirical knowledge was had of many 
processes, chemical in their nature, long 
before there was any true conception of 
their character. 

124 



Of the older nations the Egyptians 
were probably most favored with knowl- 
edge of this description. They were 
familiar wnth certain metallurgical pro- 
cesses ; for instance, the working of iron 
and its tempering ; gold was by them 
fashioned into ornaments, the rich mines 
of Nubia furnishing them with most of 
this precious metal. 

To them was known the art of potter}^ 
the glazing of earthenware and the use 
of colored enamels. The manufacture 
of glass was also practiced in Eg^'pt and 
is supposed to have originated through 
an accidental fusion of sand and soda, 
in the fluxing of gold. The making of 
glass vessels was carried on extensively 
in Thebes and even the making of arti- 
ficial gems of glass was known in Egypt 
in its early days. 

Dyeing fabrics and the use of mor- 
dants for the purposes of fixing certain 
colors on cloth was known to both the 
Egyptians and Phoenicians. The former 
also used chemical substances in their 
practice of the healing art and in the 
embalming of their dead. 

The tanning of leather by oil and later 
by means of bark was practiced by some 
nations of old. The use of soaps — com- 
125 



pounds of fats and an alkali — was known 
in Germany and in Gaul, even in the 
times of Pliny ; the purifying of clothes 
by the burning of sulphur is also men- 
tioned by this author. 

Acetic acid, in the form of vinegar, 
w^as another chemical agent with the 
properties of which antiquity w^as ac- 
quainted. This is apparent from the use 
Cleopatra is said to have put it to as a 
solvent for some valuable pearls ; this 
solution she drank, the act being 
prompted by her desire to gain the dis- 
tinction of having partaken of the most 
costly banquet that could be furnished. 

Technological chemistry finds a wdde 
field of usefulness in the treatment of 
many substances which occur in nature 
and which possess a certain value even 
in their crude, natural condition, but 
which can be much improved in quality 
and in value by appropriate processes. 

Thus it is probable that the sugar- 
cane, as such, serv^ed as food before any 
attempt w^as made to express its juice 
and to boil the same into syrup. It is 
likely that this practice originated in 
India. 

The first making of solid sugar must 
be placed somewhere between the fourth 
126 



and the seventh century of our era, pro- 
bably nearer to the latter than the former 
date. The earliest description given of 
its manufacture is by a Chinese traveler, 
Hiuen-Thsang, who saw the process 
carried on in India and who assigned to 
the solid sugar the name Chimi — a 
Chinese term signifying ' ' stone-honey. ' ' 

Even a few centuries ago sugar was 
regarded as a luxury. In 1372 sugar 
was valued in France at five dollars a 
pound ; at the close of the sixteenth 
century its price in that country was 
still almost a dollar per pound and similar 
values obtained elsewhere. 

In view of such figures it does not 
seem difficult to place credence in the 
tale of the thrifty housewives of New 
Amsterdam, who, so tradition affirms, 
were wont to provide but one lump of 
sugar, fastened by a string to the rafters 
of the dining-room, for the common use 
and enjoyment of the household. Surely 
an impressive object-lesson on the diffi- 
culty of attaining to the sweets of life ! 

But now, thanks in great measure to 
the advance of technological chemistry, 
sugar has become a cheap food-staple of 
many countries, the total world pro- 
duction of this article — ''crystallized 
127 



sunshine' ' as it has so aptly been termed — 
now approximating to seven millions of 
tons per annum, and representing a 
value of many millions of dollars. 

Coal tar is the basis of many brilliant 
colors and of many valuable medicinal 
preparations. From it there has also 
been obtained a sweetening agent, sac- 
charin, which of late years, under 
various names, has been offered as a 
substitute for sugar. 

Saccharin, or, to give it its proper 
chemical appellation, anhydro-ortho-sul- 
phamid-benzoic-acid, is a compound of 
the elements carbon, hydrogen, oxygen, 
sulphur and nitrogen ; it was discovered 
in 1879. It is a white, crystalline sub- 
stance, soluble, though not readily so, in 
cold water and is characterized by an 
intensely sweet taste ; its sweetening 
power is estimated to be, for equal 
w^eights, from three hundred to five hun- 
dred times that of pure sugar. 

While saccharin and other similar sub- 
stances may have some value as medi- 
cinal agents, their attempted substitution 
for sugar in the preparation of food and 
drink is decidedly reprehensible. Not 
only is sugar a true food, which saccharin 
is not, for taken into the system it is 
128 



eliminated unchanged, but there is 
abundant evidence on record establishing 
the fact that saccharin interferes with 
the proper exercise of the digestive 
function. In some instances even de- 
cidedly injurious effects on men and on 
animals have followed the use of this 
preparation. 

Many attempts have been made to 
produce food- substances synthetically. 
While it is claimed that the syntheses of 
sugar and albumen have been accom- 
plished, yet we are to-day as far as ever 
from having achieved any practical 
results along these lines. 

In some instances, however, valuable 
results have been obtained in modifying 
certain natural products in such a man- 
ner as to fit them for consumption as 
food-stuffs. An illustration in point is 
the manufacture of oleomargarine, but- 
terine or artificial butter, as it is called, 
which dates back to the experiments of 
Mege-Mouries, in 1870. 

In a tank heated with steam he ren- 
dered carefully washed beef-suet with 
some water, a little potassium carbonate 
and some pepsin. After digestion of the 
mixture for the proper length of time 
and after the melted fats had risen to 
129 



the surface, some salt was added and the 
fat was removed. It was allowed to cool, 
to permit of the crystallizing out of 
some of its constituents, and the fluid oil 
remaining, the oleopalmitin, was squeezed 
out by presses. To the oil thus obtained 
some milk or cream and a little butter- 
color were added, the mixture w^as well 
churned and salted and was then ready 
for the market. 

Leaf-lard is now largely used as the 
crude material in this process. In cold 
weather a little pure cottonseed oil is 
added to it in order to give an improved 
texture to the finished product. This 
industry has attained to considerable im- 
portance. 

Endeavors have also been made to- 
furnish the essence of foods in a compact 
form. For it is possible to put much 
food into a condensed form in which it 
will keep properly for a considerable 
length of time. Food tablets have been 
prepared of soup, of beef, of milk and of 
eggs, forming as it were, the very essence 
of nutriment. 

But very grave doubts exist whether 
food in such a form can and will be pro- 
perly assimilated by the animal system ; 
in fact, some experiments made a year 
130 



or two ago by some United States troops 
in Colorado, with the so-called emergency 
ration, returned a very decisive negative 
in answer to the question. 

In this connection reference may not 
be amiss to the interesting fact, that of 
late the preparation of carbonated liquids 
has been made very convenient through 
the introduction of small iron capsules 
charged with liquefied carbonic acid ; the 
capsules contain each about two grammes 
of the liquefied gas, a charge amply suffi- 
cient for the conversion of at least a 
quart of water, or other liquid, into a 
sparkling, refreshing beverage. 

However, it would lead too far afield, 
even should one only attempt to indicate 
all the many chemical processes to which 
so great a number of the necessities, 
and the comfojts of our daily life are 
owing. 

As furnishing a basis for many of these 
industries, there would have to be consi- 
dered the manufacture of the mineral 
acids — hydrochloric, sulphuric and nitric; 
also the preparation of sodium carbonate 
and of other alkaline products. 

The manufacture of textile fabrics of 
various materials — silk , wool , cotton , linen 
— would have to claim our attention. So 

131 



would the preparation of many colors 
and dyestuffs derived from animal, vege- 
table and mineral sources ; the art of 
pottery and ceramics ; the manufacture 
of paper, of ink, of matches ; the com- 
pounding of gun-powder and of smoke- 
less powders, of nitro-glycerine and of 
other high explosives, with their power- 
ful mission in peace and in war. 

Besides, the making of sugar, the pre- 
paration of starch, of flour and glucose, 
the manufacture of alcoholic beverages 
of various kinds, the preservation of cer- 
tain foods — one and all might be studied 
and called upon to bear witness to the 
importance of chemistry in its applica- 
tions. 

But, as it is not feasible to discuss all 
these in detail, interesting as it might be, 
there shall here be chosen in illustration 
but a few instances where the creative 
power of chemical science stands clearly 
revealed. 

The preparation of artificial silk from 
cellulose is an instance in kind. Cellu- 
lose is the fundamental constituent of 
plant structure ; it forms a material part 
of the solid matter of every plant. In its 
chemical composition it is allied to starch, 
being, like starch, a compound of carbon, 
132 



of hydrogen and oxygen and having the 
same percentage composition as starch. 

Cellulose is insoluble in water and in 
alcohol, it is tasteless and is not a 
nutrient. In the process here to be con- 
sidered, the cellulose is brought into so- 
lution by treatment with chloride of zinc, 
and this solution is then forced in fine 
jets into a fluid like alcohol or acetone. 
This causes the precipitation of the cellu- 
lose in the form of fine continuous 
threads ; the reagents are dissolved and 
w^ashed out, leaving only the desired 
product. The threads so obtained can 
be colored at will ; they can also be made 
waterproof and can of course be woven 
into fabrics of any desired shape and 
size. The finished article resembles silk 
so closely that even connoisseurs of the 
silkworm's product cannot always distin- 
guish between the latter and its fLii-de- 
Steele rival. 

In this case it is a substance of animal 
origin which is skilfully imitated by 
chemical processes ; in the manufacture 
of artificial India rubber w^e have an in- 
stance of the substitution, after the 
proper treatment, of one vegetable pro- 
duct for another. 

An English chemist, \V. A. Tilden, 
133 



discovered that a peculiar liquid sub- 
stance, isoprene, which had previously 
been obtained by the destructive distilla- 
tion of India rubber, could be obtained 
by the influence of heat upon oil of tur- 
pentine, rape-seed, linseed and various 
other vegetable oils. 

Isoprene is a compound of carbon and 
hydrogen ; it boils at a low temperature, 
about 40° Fahrenheit, and is converted, 
by treatment with strong mineral acids, 
hydrochloric acid, for instance, into a 
solid which is tough and elastic and 
which, also in other respects closely re- 
sembles India rubber. Many attempts 
have been made to provide synthetic sub- 
stitutes for both gutta percha and India 
rubber ; the process here referred to for 
obtaining the latter certainly seems a 
promising one, if only it can be properly 
controlled on a manufacturing scale. 

Many essential oils and other organic 
substances have been synthetically pre- 
pared. Among them benzaldehyde, the 
principal constituent of oil of bitter al- 
monds, oil of cinnamon, cumarin — to 
which the Tonka bean owes its delicate 
aroma — and vanillin, the odorous prin- 
ciple of the vanilla-bean. This vanillin 
is made from coniferin, a substance which 

134 



occurs in spruces, in firs and in larches. 

Even the flower's subtle charm, its 
perfume, needs no longer be extracted 
from the blossoms ; for the odors of the 
heliotrope, the violet, the lilac and ger- 
anium, these and many more, can now 
be made in the laboratory and are as 
fragrant as though they owed their ex- 
istence to the favored children of the 
dew and the sunshine. 

Possibly one of the most striking 
achievements of technological chemistry 
is presented by the wonderful array of 
beautiful and brilliant colors w^hich the 
chemist's art has called forth from coal- 
tar and from other apparently most unpro- 
mising sources. The great and extensive 
coal-tar color industry is built, in great 
part, upon the exhaustive studies of the 
famous German chemist, x\ugust Wilhelm 
von Hofmann, a man in whom there were 
combined to a rare degree the essential 
qualifications which mark the scientific 
investigator, the teacher and the scholar. 

The aniline colors now number several 
hundreds and have almost wholly re- 
placed the coloring matters formerly 
used — indigo, madder- root, cochineal, 
safflower and the yellow dye-woods. 

Perkin, in 1S56, made mauve from 

135 



aniline, one of the constituents of coal- 
tar oil. This was the first aniline dye to 
be prepared on a large scale. 

A synthesis in organic chemistry which 
has produced far - reaching results in 
several directions, was the artificial pre- 
paration of alizarin by Grabe and Lieber- 
mann. Alizarin is one of the coloring 
matters which occur in the madder-root. 
Its name was bestowed upon it by its 
discoverers, Colin and Robiquet, in 1826, 
the term being taken from the oriental 
appellation of madder, alizari. 

The root of this plant has been used 
in Eg3'pt and in India, since time imme- 
morial, for the dyeing of cloth ; wrap- 
pings found on mummies proved to have 
been colored by this substance. The 
culture of the madder plant was also 
practised extensively in Holland, in 
France and in Alsace, and about forty 
years ago the total annual production of 
madder was not far from five hundred 
thousand tons. 

Grabe and Liebermann found, as be- 
fore stated, that alizarin could be artifi- 
cially prepared ; they obtained it, by a 
series of ingenious chemical reactions, 
from anthracene, a constituent of coal- 
tar. This was the first instance of the 
136 



o 



synthethic production of a colorin 
principle which had formerly been 
obtained exclusively from a vegetable 
source. 

One of th® important results of this 
famous discovery was the turning over 
to agriculture for its purposes of vast 
tracts of land, w^hich had up to that time 
been used for the cultivation of the 
madder-root. Grabe and Liebermann's 
achievement also, incidentally, stimu- 
lated greatly the coal-tar industries and 
increased materially the manufacture of 
caustic soda and of sulphur trioxide. 

Another instance, w^here synthetic 
chemistry produced a color that had for 
many centuries been obtained only from 
plants, we have in the artificial manufac- 
ture of indigo. This substance was used 
very long ago in India as w^ell as in 
Egypt. In Europe, the w^oad, w^hich 
also belongs to the plants that produce 
indigo, w^as for ages the chief source of 
supply of this dye ; its use by the Gauls 
and by the ancient Britons is clearly 
-established. In Germany its cultivation 
was practised as early as the sixth cen- 
tury and was carried on for many centu- 
ries thereafter. But gradually woad was 
supplanted by indigo and the use of this 

137 



substance as a blue pigment and as a 
dye became general. 

The chemical composition of indigo 
received attention at the hands of several 
chemists. Fritzsche, in 1840, distilled 
indigo with caustic soda and secured a 
substance which he called aniline. This 
term is derived from the Sanscrit appel- 
lation 7iila, the indigo-plant, the word 
7iila signifying dark-blue ; as a matter 
of interest it may here be remarked that 
the name of the river Nile is said to be 
traceable to the same source. 

Many chemists were concerned with the 
investigation of indigo. To name but a 
few, we have lyaurent, Erdmann, Baeyer, 
Knop, Emmerling and Nencke. The 
last named succeeded, in 1875, in obtain- 
ing a small amount of artificial indigo by 
the action of ozonised air on indol. At 
present several methods of indigo-syn- 
thesis are known. 

The synthetical preparation of ultra- 
marine, a substance which replaced the 
costly lapis lazuli used in the painter's 
art, was effected after chemical analysis 
had revealed its quantitative composi- 
tion. This will serve as an illustration 
of a mineral substance successfully pro- 
duced in the laboratory and leading to 
138 



"the establishing of an important manu- 
facturing industry. 

Any consideration of technological 
chemistry, however brief, would be in- 
complete without at least a passing refer- 
ence to a recent achievement which is 
fraught with great possibilities for the 
future of many chemical processes — 
reference is made to the liquefaction of 
air on a commercial scale. 

The possibility of the liquefaction of 
air, in quantity, was demonstrated in 
1893 by James Dewar, of Edinburgh; 
Olszewski, of the University of Cracow, 
claims to have obtained this substance in 
small quantities even in 1884. 

Dewar' s method of procedure consisted 
in making use of liquefied carbonic acid 
or of ammonia, which, by its evaporation 
ensured the liquefaction of another gas, 
ethylene. This liquid was in turn em- 
ployed to cool and to liquefy still other 
gases and liquid air was finally obtained 
as the end-result of a series of such oper- 
ations. 

It proved, however, a costly treasurCj 
Dewar estimating the expense of obtain- 
ing a quart of liquid air at something 
more than two thousand dollars. 

It remained for the practical ingenuity 

139 



of an American, Charles E. Tripler, of 
New York, to devise a process by which 
liquid air can be obtained so readily and 
at a cost sufficiently low to make it avail- 
able for many purposes and in any quan- 
tity desired. 

Mr. Tripler' s process is based on the 
principle that gases which have been 
subjected to great pressure absorb much 
heat on being again allowed to expand. 

B}' means of a forty horse-power en- 
gine, provided with three pistons fur- 
nishing respective!}' sixt}', three hundred 
and two thousand pounds of pressure to 
the square inch, air in liquid form is 
produced solely through the aid of ordi- 
nary air which has been subjected to 
cooling and to these pressures. 

The temperature of the air to be liqui- 
fied is lowered to 312° below zero on 
Fahrenheit's scale. At this point it 
turns into a liquid that is practically 
colorless. 

Air, as is well known, is essentially a 
mixture of oxygen and nitrogen — by 
volume, approximately one-fifth of the 
former and four-fifths of the latter gas. 
Nitrogen evaporates more rapidly from 
liquid air than oxygen and, in conse- 
quence, liquid air undergoes changes iu 
140 



its composition on suffering evaporation ; 
it grows constantly richer in oxygen. 

The chemical and physical properties 
of most bodies when brought into contact 
with liquid air are so wholly unlike the 
properties they exhibit at ordinary tem- 
peratures, that their study under these 
novel conditions seems like the opening 
up of a new realm to the explorer — an 
Arctic region, as it were, replete with 
wonders. 

It must certainly be counted a great 
triumph of Science that she can thus 
impress into service the forces of Nature, 
and produce a cold so intense, that, by 
comparison with it, the lowest tempera- 
ture ever recorded by intrepid explorers 
of the frozen North sinks into insigni- 
ficance. 

Liquid air when poured over ice boils 
at once and becomes transformed into 
vapor. As its temperature is more than 
300 degrees below the temperature of 
ice, this result, startling as it seems, is 
inevitable. Thrown into a vessel of 
boiling water, liquid air instantly changes 
the boiling water into ice ; a jet of steam 
forced into liquid air immediately con- 
geals into glittering crystals of frost. 

Mercury, immersed in this novel re- 
141 



agent, becomes a solid, which is so hard,, 
that, appropriately shaped, it can to alt 
intents and purposes be used as a ham- 
mer as long as the magic spell of the 
frost-giant endures. 

Most metals and many other substances 
turn brittle as glass when they are sub- 
jected to the action of liquid air. On 
account of its richness in oxygen, con- 
stantly increasing, it will be remembered,, 
as its evaporation progresses, the pre- 
sence of liquid air readily ensures com- 
bustion. Wires of iron and steel will, 
w^hen ignited, burn freely in this liquid — 
itself so intensely cold. 

Employment of liquid air as the motive 
power in engines of all kinds, application, 
of its tremendous expansive and explo- 
sive force to the purposes of industry 
and of war, mark but a few of its many 
uses which the future will witness. 

As soon as man shall have learned to 
perfectly control this new and powerful 
agent — advances in that direction have 
even now been made — it stands unques- 
tioned that it will prove a potent factor 
for the good of mankind and the pro-^ 
gress of civilization. 
Pharma- The beginnings of pharmaceutical, 
chemistry must be traced to the age of 
142 



iatro-chemistry, for at that period the Chem* 
preparation of medicines was the chief 
aim of chemistry. 

Paracelsus may be regarded as one of 
the founders of pharmacy, inasmuch as 
he introduced into medicine the use of 
many chemical preparations employed 
even to this day. He prescribed as 
drugs, many metallic compounds ; among 
others salts of copper, of lead, of arsenic, 
of mercury and antimony. In the use of 
the last named he had, however, been 
preceded by Basil Valentine. Tincture 
of iron, dilute sulphuric acid, various 
essences and laudanum were also among 
the many curative agents employed by 
Paracelsus. 

The reckless manner in which some of 
his followers used metallic preparations 
in their medical practice caused much 
trouble and discussion, and finally edicts 
against the use of such substances were 
issued. But even some of the adherents 
of the new school, that is to say, the 
school of Paracelsus, did not fail to per- 
ceive that there was not a little in the 
teachings of their master that might be 
discarded to advantage. Two notable 
men of this class were Croll and Van 
Mynsicht, the latter of whom intro- 
143 



duced tartar emetic into pharmaceutical 
practice. 

Croll first made use of sulphate of pot- 
ash and ere long the alkaline salts came 
to be of great importance in medicine. 
Among those employed were the chloride 
and the carbonate of potash ; the sul- 
phate of sodium — Glauber's salt, as it is^ 
now generally termed — was then desig- 
nated as sal mirabile and was greatly 
prized by physicians on account of its 
valuable properties. The medicaments 
used gradually increased in number ; 
nitrate of silver, various salts of acetic 
acid, salt of sorrel, acid juices of fruits, 
benzoic and succinic acids and man>^ 
other substances were tried and added to 
the stores of pharmacy. Spirits of wine,, 
the aqua vitae of the alchemists, was 
turned to new account in the preparation 
of tinctures and of various essences. 
Valerius Cordus, a German physician, 
is said to have been the first to make 
ether from alcohol by means of sulphuric 
acid. 

Within the past decades the skill of 
the pharmaceutical chemist has been 
directed to the discovery and the pre- 
paration of remedies which are not found 
in Nature, as well as to the synthetic 
144 



manufacture of many drugs which she 
does offer. The introduction of chloral 
hydrate, salicylic acid and antipyrin pro- 
bably inaugurated this new departure ; 
to-day there are known long lists of 
h3^pnotics, narcotics and antipyretics 
that claim coal-tar or similar materials 
as their parent-substance. Certain glands 
and other organs of animals are alsO' 
made to yield preparations which find 
valued application in the correction of 
some of ' ' the ills that flesh is heir to. ' ' 

One of the important lines of investi- 
gation lately entered upon in pharma- 
ceutical chemistry is the attempt to trace 
the relation between the chemical com- 
position of drugs and their physiological 
action. Some advances in this direction 
have even now been made ; what vast 
and far reaching consequences would 
follow the solution of this problem, the 
fulfillment of this day-dream of more 
than one eminent physician and chemist,, 
can hardly be foretold. It would cer^ 
tainly mark a new era in the history of 
the practice of medicine. 

During the second half of the last, and 

the earlier years of this century, the 

pharmaceutical profession was charged 

with the keeping of the best interests of 

145 



chemistry, through fostering the growth, 
and development of many of its eminent _ 
disciples. In this connection one need- 
but recall the names of Scheele, Vauque^ 
lin and Klaproth ; many others might 
easily be added to the list. Among the 
institutes of pharmacy of note in their 
time, the Trommsdorff Institute, estab- 
lished in 1795 at Erfurt, perhaps deserves^ 
special mention. 

Toxi- It was a sad, but perhaps an unavoid- 
and ^t)le outcome of conditions that an. 

Legal increasing knowledge of the potent 
istry powers inherent in many drugs and 
chemical preparations should have led 
to occasional abuse and to their applica- 
tion for criminal purposes. A recital 
merely of crimes which have passed into 
history and which have been executed 
by the aid of poisons, w^ould form a long 
and thrilling tale. But the advances 
made in analytical chemistry have for- 
tunately made it possible for the science 
herself to be the Nemesis of those who 
misuse her gifts to further unlawful 
designs. 

Toxicology, which embraces a knowl- 
edge of the poisons, their effects and 
their detection, has of late years met 
with increased attention and study, and 
146 



now it would prove rather an exceptional 
instance where the criminal use of a 
poison could not be detected and proven. 

Chemical means and methods are also 
often employed in other instances to aid 
justice in tracing crime and in fastening- 
the charge upon the guilty. The detec- 
tion of forgeries in documents, the exam- 
ination of blood and other stains, the 
determination of fraudulent and injurious 
adulterants in foods and in drugs, all 
come properly within the scope of chem- 
ical investigation and control. 

The domain of physiological chemistry Medical 
is broad in scope. Originally its aim P^em- 
was a study of the various tissues, the 
fluids and the solid components of the 
animal organism. Among the early 
investigators of these problems were 
Fourcroy, Vauquelin, Chevreul and La- 
voisier ; the latter giving expression to 
his belief that the processes of life were 
chemical in their nature. 

Methods of analysis adapted to the 
requirements and calculated to overcome 
the peculiar difficulties of physiological 
chemistry were gradually evolved. 
Notable questions that were elucidated 
by their aid and through most painstak- 
ing research were, the composition of 
147 



bone-matter, the constitution of blood. 
and the phenomenon of its coagulation, 
the composition of the gastric juice, of 
milk and of other secretions of the animal 
body, including the character and proper- 
ties of the various constituents of urine. 

Experimental study of the all-important 
question of animal nutrition was initiated 
and conducted by Justus von Liebig ; 
his investigations and deductions regard- 
ing metabolism were a revelation to his 
contemporaries and aided materially in 
bringing about abandonment of the 
belief in the mysterious power of the so- 
called ' ' vital force. ' ' 

Von Liebig appreciated the different 
functions of the albumenoids, of protein- 
and gluten, as tissue and muscle builders, 
and of the carbohydrates, sugar and 
starch, and of the fats as heat producers. 
Since his days the problems of nutrition 
and the composition of nutrients have 
never failed to claim the attention of 
eminent workers. Virt, Pettenkofer, 
Ranke, Atwater, Wiley, are but a few of 
those who have enriched physiological 
chemistry in this particular direction by 
their labors. 

When a fair knowledge concerning the 
chemical composition of the various con- 
143 



stituents of the animal economy had 
been gained, investigation was directed 
into new channels ; study was attempted 
of the relations which these various sub- 
stances bear to each other, of the specific 
functions each has to perform and of the 
conditions under which these various 
substances are produced and destroyed. 

Well-known among the men active in 
such researches are Preyer, Hoppe- 
Seyler, Virchow, C. Ludwig, Hammar- 
sten and Chittenden. 

The poisons which are formed in de- 
caying animal matter, the so-called 
cadaver-alkaloids or ptomaines, w^ere first 
investigated by Selmi. On account of 
the highly poisonous character which 
some of these possess, Brieger named 
them toxines. 

When it had been ascertained that 
toxines of various natures are produced 
also in the progress of some of the 
diseases most fatal to human life, great 
skill and energy were brought to bear 
upon the seeking of antidotes for these 
poisons, and in this connection are to be 
recorded some of the most wonderful 
achievements of bacteriology and chem- 
istry — the discoveries leading to the use 
of the so-called anti-toxines. 
149 



Here there will be recalled the dis-- 
covery b}^ lyouis Pasteur of the specific 
agent by which that most terrible of 
diseases, hydrophobia, can be mastered ;• 
the preparation of an anti-toxine with 
which the ravages of diphtheria have, 
in many instances, been successfully 
checked ; the preparation of Koch's 
serum by which the existence of tuber- 
culosis in animals can be diagnosed and 
in consequence of which precautionary 
measures against the spread of this mal- 
ady can be taken. 

The first suggestion of producing unv 
consciousness, anaesthesia, through the 
inhalation of gases, is credited to Sir 
Humphry Davy. At least he was famil- 
iar to some extent with the properties 
of laughing-gas — nitrous oxide, as the 
chemists call it. 

The anaesthetic property of ether — a 
substance discovered by Valerius Cor- 
dus, about 1530 — was commented upon 
by Paracelsus in 1541. This important 
matter seems, however, to have been 
wholly lost sight of, forgotten, until the 
time when Faraday again called attention 
to it, three hundred years after ether was 
first known. 

The inhalation of this substance as a 

150 



specific agent for relieving pain seems 
to have been first considered in October, 
1846. At that time W. T. G. Morton, 
a dentist of Boston, applied to Dr. War- 
ren, a surgeon of that city, to determine 
whether the vapor of ether could be used 
in allaying pain in surgical operations, 
as Morton had found it would do in den- 
tal practice. 

Dr. Warren soon acted upon this sug- 
gestion and successfully used ether in an 
operation, in the Massachusetts General 
Hospital, Morton administering the re- 
agent to the patient at the time. Shortly 
afterT\^ards a Dr. C. T. Jackson, of Bos- 
ton, in conversation with Warren claimed 
that it was he who had acquainted 
Morton with the use of this reagent for 
dental operations. 

In 1847 an English physician, James 
Young Simpson, acting on the suggestion 
of a Mr. Waldie of Liverpool, introduced 
the use of chloroform as an anaesthetic. 

The use of anaesthetics on the one 
hand, and the method of treating wounds 
antiseptically, introduced by the English 
surgeon, Sir Joseph Lister, will ever rank 
among the most brilliant achievements 
of medical chemistry. 

The extensive studies of Pasteur on 
151 



fermentation have opened up the vast 
field of bacteriology with its wonders of 
the infinitely small. This topic is foreign 
to our present quest, but it is vividly 
called to mind in connection with the 
latest researches of E. Biichner, Tiibin- 
gen, who would relegate the phenomena 
of alcoholic fermentation entirely to 
chemical action, claiming that this va- 
riety of fermentation is due, not directly 
to the growth of the yeast-plant, but 
to a kind of ferment obtainable there- 
from. 

Hygiene, the art of preserving health, 
has of course profited largely by the 
revelations of physiological chemistry. 
Having ascertained the character and 
the nutrient value of various classes and 
kinds of food, it was but a short step to 
seek to safeguard against their adultera- 
tion, which means, at the very least, a 
lowering of their normal and proper 
value. So important a matter has this 
come to be, that many larger commu- 
nities maintain special officials for the 
sole purpose of watching and ensuring 
the purity of their food-supply. 

Many diseases can be communicated 
through the agency of food and drink. 
Among the diseases which can be so 
152 



spread are tuberculosis, scarlet and ty- 
phoid fever and cholera. In former times 
the ravages of these scourges were almost 
unchecked until their full course had 
been run, but since the true cause and 
character of many of these contagious 
and infectious diseases have come to be 
understood — thanks in great part to the 
findings and teachings of bacteriology, — 
the aid of chemistry has been invoked to 
supply remedial and preventive agents. 
An account of the properties, the uses 
and the benefits conferred by antiseptics 
and disinfectants would form a chapter 
of no slight interest in a detailed history 
of medical chemistry. 

As one of the most important and bril- 
liant researches recently made in physio- 
logical chemistry there must be noted 
the endeavor of Professor Leopold 
Schenk, of Vienna, to influence the sex 
of human offspring by regulating the 
diet of the mother. 

In his method insistence is placed upon 
the chemical nature of the food consumed 
and upon the complete combustion of 
this food in the system ; by means of 
chemical analysis a careful control is kept 
as to the regularity and the completeness 
with which this proceeds. 

153 



Schenk claims that under certain cir- 
cumstances male progeny may be pro- 
cured by aid of the influences which he 
has indicated ; creation at will of female 
offspring, he admits, is as yet beyond 
our ken. If his work bears the test of 
time and experience, a great advance irr 
physiology will have been made, and in 
part through the aid of our science. 

May we, dare we, hope that Chemistry 
the Beneficent, at whose shrine we all — 
knowingly or unknowingly — pay daily 
tribute and homage, will some time 
return answer to our pleading and reveal" 
to us the long-sought secret of Life ? 




154 



WORKS CONSULTED. 



Gladstone, J. H. The Metals Used by the 
Great Nations of Antiquity, A Lecture 
delivered at the Royal Institution^ 1898. 

Kopp, H. Geschichte der Chemie, 1843- 1847. 

Kopp, H. Beitrdge zur Geschichte der Che- 
mie, 1869. 

Kopp, H. Die Entwickelung der Chemie in 
der neueren Zeit^ 1873. 

ROssiNG, A. Einfilhrung in das Studium der^ 
theoretischen Chemie^ 1890. 

RoscoE, H. E., and Schorlemmer, C. A 
Treatise on Chemistry^ 1878. 

Sadtler, S. p. a Handbook of Industrial 
Organic Chemistry, 1891. 

Schorlemmer, C. (Smithells, A.) The Rise 
and Development of Organic Chemistry, 
1894. 

Thomson, T. The History of Chemistry, 1830- 
1831. 

Venable, F. p. a Short History of Chemistry, 
1894. 

Von Meyer, E. (M'Gowan, G.) A History of 
Chemistry f'om Earliest Times to the Pres- 
ent Day, 1 89 1. 

WiECHMANN, F. G. Lecture-notes on Theo- 
retical Chemistry, 1895. 

155 



INDEX OF NAMES. 



PAGS 

1 763-1 832. Adet, Pierre Auguste 80 

5th Century, ^neas Gazaos 19 

1490-1555. Agricola, Georg. . .15, 30, 85, no 

356-323 B.C. Alexander the Great 11 

1850- Am^lineau, E 3 

Amnael 3 

1775-1836. Ampere, Andr6 Marie 59 

384-322 B.C. Aristotle of Stagira, ir, 12, 13, 14, 

28, 32, 37 

19th Cent'y. Arrhenius, Svante 106 

1844- Atwater, Wilbur Olin 148 

978-1036. Avicenna 28 

1776-1856. Avogadro, Amadeo 59, 70 

Azazel 2 

1561-1626. Bacon, Francis, of Verulam.36, ^y 

12 14-1294. Bacon^ Roger 24 

1835- Baeyer von, Adolf 138 

1867- Bancroft, Wilder D 106 

1641-1709. Barner, Jacob 86 

15th Cent'y. Basilius Valentintts 143 

1635-1682. Becher, }. J 40, 52 

1813-1898. Bessemer, Henry, Sir 11 r 

1735-1784. Bergman, Torbern, 42, 43, 53, 80, 

93. 94, 99» 1 10, 114 
1827- Berthelot, Marcellin Pierre. 5, 108 
1748-1822. Berthollet, Claude Louis, 52, 54-5 
1779-1848. Berzelius, Jons Jacob . .57, 58, 61, 
68, 69, 70, 72, 80, 86, 93, 
96, 97, 100, 104, 115 
1792-1870. Bischof, Karl Gustav 116 

157 



PAGE 

1728-1799. Black, Joseph 44, 45, 46 

1843- Bolton, Henry Carrington. .87, 88 

1668-1738. Boerhaave,Hermann.45, 86, 91, 92 

19th Cent'y. Boullay, P. fils 72 

1627-1691. Boyle, Robert 37, 38, 40, 98 

i9lh Cent'y. Brieger 149 

1849- Brush, Charles Francis 67 

19th Cent'y. Biichner, E 152 

Budge, Wallis 108 

1707-1788. Buffon de, Jean Louis Leclerc 45 
1811-1899. Bunsen, Robert Wilhelm 

Eberhard 103, 116 

1731-1810. Cavendish, Henry, Lord, 44, 49, 54 

19th Cent'y. Cannizzaro, S 59 

19th Cent'y. Carlisle, Antony 104 

Chemmis 7 

1786-1889. Chevreul, Michel Eugene . . . 147 
1856- Chittenden, Russell Henry . . 149 

1847- Clarke, Frank\Vigglesworth,63,78 

1843- Classen, Alexander 105 

ist Century. Clemens, Romanus 2 

Cleopatra 126 

1784- Colin, Jean Jacques 136 

1827-1894. Cooke, Josiah Parsons 106 

-1544. Cordus, Valerius 144, 150 

-1609. Croll, Oswald 143, 144 

1832- Crookes, William, Sir 68, 106 

1 722-1765. Cronstedt, Alexander Fried- 
rich 93 

1766-1844. Dalton, John . . .55, 56, 57, 58, 59, 

71, 80 

1813-1895. Dana, James Dwight 115 

1 809-1882. Darwin, Charles Robert 120 

1778-1829. Davy, Humphry,Sir.68, 84,104, 150 

460-357 B.C. Democritus of Abdera 11 

1818-1881. Deville, H. E. St. Claire .... 117 

158 



PACK 

1842- Dewar, James 139 

ist Cen. B.C. Diodorus 15, 109 

1780-1849. Dobereiner, Johann Wolf- 
gang 74 

1785-1838. Dulong, Pierre Louis 60 

1800-1884. Dumas, Jean-Baptiste Andr^, 63, 

70, 72 
19th Cent'y. Emmerling 138 

Empedocles of Agrigent . . . . 11 
i8th Cent'y. Engestroem von, Gustav. ... 93 

1804-1869. Erdmann, Otto Linn^ 138 

1686-1736. Fahrenheit, Gabriel Dominik 92 
1791-1869. Faraday, Michael 69, 150 

Faust 26 

4th Cent'y. Firmicus, Julius Maternus. . . 5 
1755-1809. Fourcroy de, Antoine F., 52,96, 

147 

1825- Frankland, Edward 62, 76 

1818-1897. Fresenius, Carl Remigius ... 98 

181 1-1892. Fritzsche, F. W 138 

1745-1818. Gahn, Johann Gottlieb 93 

1778-1850. Gay-Lussac, Joseph Louis, 58, 59, 

105 

702-765. Geber 27 

1672-173 1. Geoffroy, Elienne Francois, 44, 80 

18 16-1856. Gerhardt, Carl 73 

1822- Gibbs, Oliver Wolcott. . . 105, 106 

1604-1668. Glauber, Johann Rudolph. . . 34 
1792- Gmelin, Christian Gottlob . . 97 

1788-1853. Gmelin, Leopold 70, 71, 100 

1749-1832. Goethe von, Johann Wolf- 
gang 26 

19th Cent'y. Graebe, C 136, 137 

19th Cent'y. Guldberg 106 

19th Cent'y. Hammarsten, Olof 149 

i8th,i9thC. Hare 92 

159 



1568-1631. Hartmann, Johann «3 

1755-1827. Hassenfratz, Jean Henri 80 

1743-1822. Hauy, R6n6 Just 115 

1685-1766. Hellot, Jean 44 

1577-1644. Helmont van, Jean Baptiste,3i, 

32, 33 
1734-1816. Henry, Thomas 97 

Hermes Trismegistos. . .16, 17, 18 

Herodotus 108 

i8th Cent'y. Higgins, W 56 

7th Cent'y. Hiuen-Thsang 127 

1621-1698. Hofmann, Jo lann Moritz 84 

18 18-1892. Hofmann von, A. \V 135 

1660-1742. Hoffmann, Friedrich 45 

ab't 1000 B.C. Homer 4, 8 

1635-1703. Hooke, Robert 39, 40 

1825-1895. Hoppe-Seyler, F 149 

Horos 3 

nth Cent'y. Hortulanus 16 

i8th Cent'y. Howard, Edward 97 

1769-1859. Humboldt von, Friedrich 

Heinrich Alexander. 58 
1826-1S92. Hunt, Thomas Sterry 117 

Isis 3 

j8c5-i88o. Jackson, Charles Thomas . . . 151 

7th Cent'y. John of Antioch 4 

1829-1896. Kekul6 von Stradonitz, 

Friedrich August. 77 

1859- Kemp, James Furman 117 

1824-1887. Kirchoff, Gustav Robert 103 

1750-1812. Kirwan, Richard 53, 56 

1743-1817. Klaproth, Martin Heinrich, 52, 53, 

94, 95, 114, 146 

1817-1891. Knop, Wilhelm 138 

1843- Koch, Robert 150 

160 



PAGE 

1818-T884. Kolbe, Hermann 73 

1817-1892. Kopp, Hermann 16, 19 

1630-1702. Kunkel, Johann 24 

1831- Landolt, Hans 63 

1749-1827. Laplace de, Pierre Simon ... 49 

1801-1873. La Rive de, Auguste 114 

1807-1853. Laurent, Auguste 72, 73, 138 

1743-1794. Lavoisier, Antoine Laurent, 47, 
48, 49» 50, 52, 54, 71, 80, 86, 99, 147 

_i9th Cent'y. Le Bel, J. A 77, 106 

19th Cent'y. Leemans 5 

1646-17 16. Leibnitz von, Gottfried Wil- 

helm 29 

1645-1715. Lemery, Nicolaus 43, 86, 99 

1810-1884. Lepsius, Karl Richard 109 

1540-1616. Libavius, Andreas 34, 85 

19th Cent'y- Liebermann, C 136, 137 

1803-1873. Liebig von, Justus, 71, 72, 84, 98, 

119, 148 

1827- Lister, Joseph, Sir 151 

1836- Lockyer, Joseph Norman. .. . 103 

1816-1895. Ludwig, Carl Friedrich W. . . 149 

19th Cent'y. Luckow 105 

19th Cent'y* Liipke, Robert 105 

1718-1784. Macquer, P. J 44 

1645-1679. Mayow, John 39» 4o 

19th Cent*y. M^ge-Mouries 129 

1834- Mendel^eff, Dimitri Iwano- 

witsch 74, 75 

1830-1895. Meyer von, Julius Lothar 74 

1794-1863. Mitscherlich, Eilhard, 61, 97, 115 

1852- Moissan, Henri 117, 118 

1700-1781. Monceau, Duhamel du, Henri 

Louis 44, no 

19th Cent'y. Morgan de, Jacques 107 

J838- Morley, Edward Williams. .. 63 

161 



PAGE 

19th Cent'y. Morley, Henry Forster 87 

1737-1816. Morveau de, Guyton 51, 80 

1819-1868. Morton, William Thomas 

Green 151 

1848- Muir, Matthew Moncrieff 

Pattison 87 

17th Cent'y. Mynsicht van, Adrian 143 

19th Cent'y. Nasini, R 67 

Nemesis 146 

19th Cent'y. Nencke 138 

19th Cent'y. Nernst, Walter 106 

1838-1898. Newlands, John A. R 74 

1643-1727. Newton, Isaac, Sir 29, 54 

1753-1815. Nicholson, William 104 

1832- Nordenskjold, Nils Adolf Erik 97 

19th Cent'y. Olszewski, Karl 139 

Osiris 3 

1853- Ostwald, Wilhelm, 63, 89, 105, 106 

1493-1541. Paracelsus, 24, 30, 31, 32, 34, 143, 

150 

1822-1895. Pasteur, Louis 77, 150, 151 

1838- Perkin, William Henry 135 

1791-1820. Petit, Alexis Therese 60 

1818- Pettenkofer von, M. J 148 

382-336 B.C. Philip of Macedon 11 

429-347 B.C. Plato II 

23-79. Pliny, Caius Plinius Secundus, 4, 

8, 15, 126 

ist Cent'y. Plutarch 6 

1841-1897. Preyer, Thierry Wilhelm 149 

1733-1804. Priestley, Joseph.. .44, 45, 92, 118 

1755-1826. Proust, Joseph Louis 54j 55 

1 785-1850. Prout, William 59 » 60, 63 

Pthah 4 

1813- Rammelsberg,C 116 

1852- Ramsay, William 66, 75 

162 



PAGE 

19th Cent'y. Ranke 148 

19th Cent'y. Raoult 106 

1842- Rayleigh, Lord 75 

1683-1756. Reaumur de, Ren6 A. F no 

1846- Remsen, Ira 106 

-1645. Rey, Jean 38 

19th Cent'y. Richards 63 

1762-1807. Richter, Jeremias Benjamin, 

55. 57, 58 

1415-1490. Ripley, Georg 84 

1780-1840. Robiquet, Pierre-Jean 136 

1833- Roscoe, Henry Enfield, Sir. . 86 

1798-1872. Rose, Gustav 97, 1 16 

1795-1864. Rose, Heinrich 97 

1703-1770. Rouelle, Guillaume Fran9ois . 99 

19th Cent'y, Sarasin 117 

1742-1786. Scheele, Carl Wilhelm, 

42, 43, 99, 146 

19th Cent'y. Schenk, Leopold 153 

i8th Cent'y. Schliiter, Christoph Andreas no 

1834-1892. Schorlemmer, Carl 86 

19th Cent'y. Selmi 149 

-1646. Sendivogius, Michael 28 

4B.C.-65A.D. Seneca, Lucius Annaeus 15 

1742-1809. Senebier, Jean 118 

1572-1637. Sennert, Daniel 34 

Seth 5 

19th Cent'y. Seubert, Karl 63 

1811-1870. Simpson, James Young 150 

19th Cent'y. Smith, Edgar F 105 

1660-1734. Stahl, Georg Ernst, 40, 42, 4$, 

52,86 

1813-1891. Stas, Jean Servais 63, 64 

1614-1672. Sylvius, Franz de le Boe . . .31, 34 

17th Cent'y. Tachenius, Otto 34 

1825-1878. Taylor, Bayard 26 

163 



PACK 

1761-1815. ^Tennant, Smithson 97 

150-230. ' Tertullianus ^ 

640-550 B.C. Thales 14 

4th Cent'y. Themistos Euphrades 19 

1777-1857. Th^nard, Louis Jacques 105 

1773-1852. Thomson, Thomas 57 

42 B.C. -37 A.D.Tiberius, Claudius Nero 

Caesar 8, 9 

1842- Tilden, W. A 135 

19th Cent'y. Travers, Morris W 6S 

1864- Trevor, Joseph E 107 

1849- Tripler, Charles E 140 

1776-1850. Troost, Gerard 117 

1852- Van*t Hoff, Jacobus Hen- 

drikus 77, 106 

1763-1829. Vauquelin, Louis Nicolas, 53. 96, 

114, 146, 147 

182 1- Virchow, Rudolf 149 

19th Cent'y- Virt 14S 

19th Cent'y. Waage 106 

19th Cent'y. Waldie 151 

1778-1856. Warren, John Collins 151 

1815-1884. Watts, Henry S& 

1740- 1 793. Wenzel, Carl Friedrich 55 

1844- Wiley, Harvey Washington. . 148 

1835- Wislicenus, Johannes 77 

1800-1882. Wohler, Friedrich, 71, 96, 97, lor 
1766-1828. Wollaston, William Hyde, 

57, 93 » 9S 
18 17-1884. Wurtz, Charles Adolphe. .47, 106 
5th Cent'y. Zosimos of Panopolis 2, 4, 6 



164 



SUBJECT INDEX. 



PACK 

Academia del Cimento 92 

Acetic acid. .^ 126 

Acetylene 114 

Aetherin theory 71 

Air, an element 11,13 

Albumenoids, functions of 14S 

Alchemistic symbols 79 

Alchemists, early writings of 5 

Alchemy 16 

Alchemy, aims of 21 

Alchymia 34, 85 

Alkahest 33 

Alizarin, synthesis of 136 

Alloys Ill 

Alloys, colors of 19, 121 

Aluminium iii 

Aluminium cup of Tiberius 8 

Ammonium cyanate loi 

Anaesthetics 150 

Analysis, chemical 8a 

Aniline 13S 

Aniline colors 135 

Animal chemistry 99, 

Animal nutrition 148: 

Anthracene 136 

Anti-phlogistic theory 47 

Antiseptics 153, 

Anti-toxines i49> 

165 



page: 

Argon 66, 75 

Aristotle, philosophy of. 1 1 

Aqua vitae , 144 

Assaying 93 

Atom, definition of 82 

Atomic theory 55 

Atomic theory, attacks on 70 

Atomic weights and equivalents 62 

Atomic weights, determination of 63 

Atomic weights table 65 

Ausfiihrliches Handbuch der Analytischen 

Chemie 97 

Avogadro's hypothesis 59 

Bacon, teachings of 36 

Balance, analytical 91 

Benzaldehyde 134 

Benzoyl 71 

Beryllium, discovery of 96 

Berzelius, analytical work of 96 

Black's research on alkaline carbonates 46 

Blow-pipe analysis 93 

Bolton's Bibliographies 87 

Boyle's investigations 37 

Bronze 108, 11 1 

Burning glass, combustion effected by 92 

Caesium, discovery of 103 

Calcium carbide 114 

Calx ot metals 41 

Carbides 114 

Carbohydrates, functions of 148 

Carbonic acid, liquefied 131 

Carbon-steel ^ . iir 

Carborundum 114 

166 



PAGR 

Catalogue of Scientific Periodicals 87 

Cellulose 132 

Chemia 6 

Chemical analysis 88 

Chemical combination, views on 54 

Chemical equations 83 

Chemical equivalents 61 

Chemical knowledge, early 7 

Chemical nomenclature 80 

Chemistry, early instruction in 84 

Chemistry, language of 78 

Chemistry, manuals of 84 

Chemistry of the stars 103 

Chemistry of Three Dimensions 78 

Chemistry, oldest manuscript on 4 

Chemistry, origin of 2 

Chemistry, origin of the term 5 

Chloroform 151 

Chlorophyll 123 

Chromium, discovery of 96 

Chro7iicles of John of Antioch 4 

Chymia Philosophica 86 

Cinnabar no 

Coal-tar colors 135 

Coins, earliest 108 

Color of leaves 123 

Combustion-theory 39 

Compound of Alchyynie 84 

Compounds, symbols of 82 

Coniferin 134 

Conjugate compounds 73 

Constitution of metals, alchemists' view of. 25 

Copper, early use of 108 

Copper-coating of vessels 112 

Coronium 67 

167 



PACK 

Cours de Chymie , ,86, 99. 

Crucibles, silver 96 

Cumarin 134 

Cup ofTiberius 8 

Dalton's atomic theory. . . . i 56 

Democritus' primal form of matter 11 

Dephlogisticated air 49 

De re tnetallica 30, 85 

Diamond, composition of 97 

Diamond, synthesis of. 117 

Didactic chemistry 83 

Dictionary of Chemistry 86 

Diseases communicable through food 152 

Disinfectants 153 

Docimacy 94 

Drugs, relation between composition and 

action 145 

Drugs, synthesis of 145 

Dualistic theory 69 

Dulong and Petit's law 60 

Dyeing, early knowledge of 9 

Dyads, definition of 62 

Early systems of natural philosophy 10 

Earth, an element iii 13 

Earth-worms 120 

Egypt, the home of alchemy 16 

Egyptian symbol of immortality 154 

Electro-chemical theory 68 

Electro-chemistry 104 

Electrolysis of chemical compounds 104 

Electro-metallurgy 113 

Electro-plating 114 

Electrum 108 

168 



pack: 

Elemenia Chemiae 86- 

Elements de Chimie 86 

Elements, newly discovered 66 

Elements, symbols of 82 

Elixir, great and small 22 

Embalming, early practice of. 9 

Emerald tablet, the 17 

Equations, chemical 83 

Equivalents, Gmelin's table of 71 

Era of quantitative investigation 52 

Essential oils, synthesis of 134 

Ether 144, 150 

Etherion 68 

Faraday's law 69 

Fermentation 152 

Fertilizers 122 

Fire, an element 11, 12 

Fixed air 46 

Food adulteration 152 

Food, synthesis of 129 

Food-tablets 130 

Formulae, chemical 82 

Fimdameyita Chemiae 86 

Gallium, discovery of 75, 103 

GaZ'sylvestre ... :i^2> 

Geological chemistry 116 

Germanium, discovery of 75 

Glass, manufacture of 9, 125 

Glauber's salt 144 

Gmelin's table of equivalents 71 

Gold, early use of 107 

Gold, philosophers* 23 

Gold, supposed constituents of 25 

169 



PAGE 



Golden fleece 4 

Gravimetric analysis 90 

Handbuch der Miner alchemie 116 

Hare's hydrogen apparatus 92 

Helium, discovery of 66, 75 

Henoch 2 

Hermetic art 21 

Historia naturalis 4 

Homilies 2 

Hooke and Mayow's theory of combustion. 39 

Humus-doctrine 119 

Hygiene 152 

latro-chemistry 30 

Idria, mercury mines of no 

Immortality, Egyptian symbol of. 154 

Indestructibility of matter 32 

India rubber, artificial 133 

Indigo, synthesis of. 137 

Indium, discovery of 103 

Indol 138 

Inorganic and organic substances ico 

IntroductioJi to Chemical Analysis 96 

Iridium, discovery of 97 

Iron, Bergman's investigation of no 

Iron, early use of 109 

Isis and Osiris 6 

Isomorphism 61, 115 

Isoprene 134 

Journal of Physical Chemistry 106 

Klaproth's work 94 

Koch's serum 150 

Krypton, discovery of 66 

170 



PAGB 



Lamps, perpetually burning 27 

Language of chemistry 78 

Lapis lazuli 138 

Laudanum, early use of 143 

Laughing gas 150 

Lavoisier's work 47 

Law of Dulong and Petit 60 

Law of volumes/ 58 

Leaves, color-changes of. 123 

Legal chemistry 146 

Lehrbuch der Chemie 86 

Lehrbuch der Chemischen Geologie 116 

Lemery's classification 99 

Leyden papyrus 4 

Liquid air 139 

Madder 136 

Magisterium, the great 21 

Manuals of chemistry 84 

Manuscript, oldest, on chemistry 4 

Mathesis 5 

Matter, Aristotle's primary qualities of 12 

Matter, indestructibility of 32 

Mauve 135 

Mead 10 

Medical chemistry 147 

Mendel^efTs predictions 75 

Mercury of the alchemists 25 

Metal calxes 41 

Metallic pigments 113 

Metallurgical chemistry 107 

Metals, transmutation of 19, 21 

Metargon, discovery of 66 

Meteorites, diamonds in 117 

Meteorites, early analyses of 97 

171 



PAGE 

Micrographia 39 

Mineralogical chemistry 114 

Mineralogy, synthetic 116 

Monads, definition of 62 

Monium, discovery of 68 

Mordants, early use of 125 

Nagada, tomb at 107 

Natural philosophy, early systems of 10 

Neon, discovery of .... 66, 75 

New System of Chemical Philosophy. . . 57 

Nitrous oxide 150 

N®menclature, chemical 80 

Nucleus theory 72 

Nutrition, animal 148 

Oleomargarine 129 

Organic analysis and synthesis 98 

Organic and inorganic substances 100 

Origin of alchemy 16 

Origin of chemistry 2 

Origin of the word chemistry 5 

Oiiris, tomb of 3 

Osmium, discovery of 97 

Oriim philosophicum 23 

Oxygen, term first used 49 

Panacea, the great 27 

Papyrus of Leyden 4 

Perfumes, synthesis of 135 

Period of transition 36 

Periodic law 73 

Periodicity of properties 76 

Perpetually burning lamps 27 

Pharmaceutical chemistry 142 

172 



PAGE 

Philosopher's gold 23 

Philosopher's stone, descriptions of 24 

Philosopher's stone, manufacture of 22 

Philosophers stone, powers of 26 

Philosophy of Aristotle 11 

Phlogiston theory 40 

Phlogiston theory, decadence of 45 

Physical chemistry 106 

Physiological chemistry 147 

Phyto-chemistry ... i iS 

Platinum, refining of. 93 

Potassium, discovery of 104 

Proust's investigations 54 

Prout's hypothesis 59 

Proxmiate analysis 89 

Ptomaines 149 

Qualitative analysis 90 

Quantitative analysis 90 

Quantitative investigation, era of 52 

Quantivalence 62 

Quartz changed into gems 28 

Quartz formed from water 15 

Radicals 100 

Radicals, theory of 71 

Raven's head 23 

Rubidium, discovery of 103 

Saccharin 1 28 

Sal maris 78 

Sal mirabile 1 44 

Salt, definition of 34 

Scandium, discovery of 75 

Sceptical Chymist^ The 39 

J 73 



PAGB 

Scheele's investigations 43 

Schenk's theory 153 

Scholastics, teachings of 13 

Scientific Foundations of Analytical Chem- 
istry ^ 89 

Select Bibliography of Chemistry 87 

Silicides 114 

Silk, artificial 132 

Silver, early use of. 107 

Silver crucibles 96 

Silver rings 108 

Soaps, early use ol 125 

Sodium, discovery of 104 

Specific heat 60 

Spectrum analysis 102 

Spirits of wine 144 

Spread of alchemy 20 

Steel, Bessemer's process iii 

Steel, R^amur's process no 

Stereo-chemistry 77 

Stoichiometry, foundations of , 55 

Stone-honey 127 

Strontium, discovery of. 105 

Substitution theory 72 

Sugar 126 

Sulphate of potash 144 

Sulphate of sodium 144 

Sulphur, early use of 126 

Sulphur of the alchemists 25 

Swan, the 24 

Symbols, alchemistic 79 

Symbols, systems of chemical 80 

Synthesis of food 129 

Synthesis of water 50 

Synthetic mineralogy 116 

174 



PAGE 

System of Chemistry 57 

Table of atomic weights 65 

Tabula sinaragdina 16 

Teachings of scholastics 13 

Technological chemistry 124 

Temperature, measurement of .... 91 

Terra pinguis 41 

Text-book of Mineralogy 116 

Thallium, discovery of. 103 

Thermometer, construction of. 91 

Thomas-Gilchrist process iii 

Tiberius, cup of 8 

Tincture, the red 21 

Tincture, the white 22 

Tomb of Osiris 3 

Toxicology 146 

Toxines 149 

Transition, period of. 36 

Transmutation of metals 14, 19 

Treatise on Chemistry 86 

Triads, definition of 62 

Trommsdorff Institute 146 

Types, theory of 73 

Ultimate analysis 89 

Ultramarine 138 

Unitary theory 72 

Universal solvent 33 

Urea, synthesis of loi 

Valence 61 

Vanillin 134 

Vital air 49 

Vital force loi 

175 



PAGE 

Volumetric analysis 90 

Water, an element 11. 13, 14, 32 

Water, electrolysis of 104 

Water, synthesis of 50 

Water, transmutability of 15 

Wet analysis 94 

Woad 137 

Xenon, discovery of 67 

Zeitschrift fuer Analytische Chemie 98 

Zeitschrift fuer Physikalische Chemie 106 



176 



